AGARTALA, INDIA, April 13.-Although large numbers of East Pakistani secessionist leaders have been reported killed and with wholesale bloodshed continuing, several members of the movement's high command are alive and have formed a cabinet.

They include Tajuddin Ahmed, second in command to Sheikh Mujibur Rahman, whose Awami League took the steps for independence that brought West Pakistan's military crackdown.

In an East Pakistani border area visited by this correspondent, at least six secessionist leaders met to name Mr. Ahmed Prime Minister and Defense Minister of the state they call Bangla Desh, or Bengal Nation. They proclaimed Sheikh Mujib their President, although privately the secessionist leaders acknowledged that he was in prison in West Pakistan.

While the central Government, which is dominated by West Pakistan continues to announce that the situation is calm in the East and conditions are returning to normal, a far different picture emerges on the scene.

DAILY BATTLES REPORTED

Daily battles are reliably reported in many sectors. Hordes of East Pakistanis have fled the cities to seek refuge or join the secessionist army, and thousands of refugees, carrying their meager belongings in cardboard suitcases and sacks, are crossing into India for temporary haven.

This correspondent saw Pakistani soldiers burning villages to deny the resistance forces cover or hiding places. As the smoke from the thatch and bamboo huts billowed up on the outskirts of the city of Comilla, circling vultures descended on the bodies of peasants, already being picked apart by dogs and crows.

There is no way of knowing exactly how many of East Pakistan's 75 million Bengalis the army has killed, but authoritative reports from many sources agree that the figure is at least in the tens of thousands; some reports put it much higher.

The central Government officially bars all foreign newsmen from East Pakistan. But from the evidence available in secessionist held rural areas-some of which are occasionally contested by the army-the Pakistani armed forces have killed leaders and potential leaders of East Pakistan and shattered the economic base of the region in their effort to crush the independence movement.

On orders, the army-now consisting entirely of West Pakistani troops-has killed students, intellectuals, professors, engineers, doctors and others of leadership caliber- whether they were directly involved with the nationalist movement or not.

Both in military attacks and in executions, the central Government's forces killed East Pakistani Army officers and soldiers who were unable to break out and join the guerrilla forces when the army offensive began on March 25. Most of the officers' families have been killed: only a few escaped into hiding.

With the aid of air and naval bombardment, the army has destroyed food supplies, tea factories, Jute mills and natural-gas fields-the economic basis of East Pakistan.

"This has already set the country back 25 years." said a Scottish tea-estate manager who fled to India from his plantation in the northeast. "The liberation army, trying to stop the army, is blowing the bridges, railroad lines and roads. Even If they eventually win independence, they'll have to start completely from scratch again."

This man and two other estate managers who escaped with him asked that their names not be used because of their fear of reprisals against British families still in East Pakistan.

ATTACK ON "EMPTY" TRUCKS

The three evacuees reported that a convoy of nine trucks that the Pakistani radio contended had been carrying arms and ammunition from India and had been destroyed by Pakistani planes was in fact a collection of empty trucks in the yard of a tea estate.

Authoritative reports indicate that perhaps 20 to 25 per cent of the people are left in such towns as Dacca, the capital, and Chittagong and Comilla. Smaller centers are also largely deserted. Dacca had a population of about 1.5 million, Chittagong about 400,000 to 500,000 and Comilla about 100,000

In the eastern part of East Pakistan the thump of artillery fire can be heard every day in virtually every sector. After every guerrilla attack or harassment by the outnumbered and outgunned resistance troops, the Pakistani Army appears to be inflicting reprisals on the civilian population.

"The bloody cowards!" said a young Bengali lieutenant who escaped the army attempt to annihilate his battalion of the East Bengal Regiment at Comilla. "We give them fronts to shoot at. We are in uniform. But they attack civilians instead."

The secessionist army 18 desperately short of trained officers, arms, ammunition, vehicles and basic supplies. Some of the men are barefoot.

The heaviest weapon the secessionists have in any numbers is the 3-inch mortar, although they have captured a few heavy guns. The Pakistani military are using jet fighter-bombers, heavy artillery and gunboats- mostly supplied by the United States the Soviet Union and Communist China.

Pakistani charges that the Indian Government has been sending troops and weapons to East Pakistan are not borne out by this reporter's observations. No Indian troops were seen in the East Pakistani units.

The basic weapons are old Enfield and Garand rifles and some Chinese-made automatic rifles and machine guns- which the Bengalis have either captured or had brought with them when they escaped from their units.

Fewer than 10 per cent of the 300,000 men in the Pakistani armed forces were Bengalis. Nearly all of those who were not killed by the West Pakistani troops in the first days have joined the secessionist army and constitute its only trained elements.

The best available figures indicate that the trained core consists of some 3,000 members of the East Bengal Regiment, which was a regular unit, and some 9,000 members of the East Pakistan Rifles, a paramilitary unit one of whose duties was to man the observation posts on the border with India .

The rest of the secessionist force is made up of armed policemen, home guards, other poorly trained local militia and raw recruits.

Before the political crisis began to mount, the Pakistani Army had about 25,000 troops in East Pakistan. Large numbers of reinforcements have been flown over from West Pakistan, which is separated from the Eastern province by over a thousand miles of Indian territory.

Some estimates put the number of West Pakistanis at 60,000 to 80,000 most of them Punjabis and Pathans. The Punjabis in particular have traditionally held the Bengalis in disdain though both are predominantly Moslem.

Though the average amount of ammunition by the guerrilla riflemen is 30 to 40 rounds, their determination seems high, fueled in many cases by the fact that the Pakistani army has killed members of their families-and sometimes all of them.

"They have made me an orphan," said one soldier who, like many of his comrades, had glassy eyes ,and seemed unable to believe what had happened. "My life is unimportant now."

Two days ago West Pakistani troops, as they had been for several days, were burning villages on the outskirts of Comilla less than a mile from the Indian border. Their apparent purpose was to remove all cover within a five- mile radius of the airstrip. Reports indicate they are doing the same all over East Pakistan.

Maj.. Khaled Musharrof, the 32-year-old guerrilla commander in the area, sent out a 10-man patrol to harass the Pakistani troops. This correspondent accompanied the patrol, three of whose members had no shoes.

Using rice paddles to advantage, the patrol stalked to within 200 yards of the soldiers, who were ,throwing phosphorous grenades into thatch huts. The Bengalis, who had some Chinese-made automatic weapons. opened fire, which the soldiers immediately returned. The shooting was nearly constant for about 20 minutes, after which the Bengalis came scrambling back to safety over an embankment.

SHEIK MUJIB FACES TRIAL

The coordination of guerrilla units is poor and in some instances nonexistent. The Bengalis are now devoting themselves to guerrilla tactics while the army has gained control of most of the major cities and towns, including the cantonments and airfields.

With their added strength, the troops are launching forays into the countryside and sending out motorized columns to try to link up the cities they control. A few of the columns have been successful, but not many because the guerrillas have been able to cut road, water and rail links with some regularity.

Though the guerrillas were fighting on, their leaders acknowledged that Sheikh Mujib, the 51-year-old symbol of the rebel movement, was recently awaiting trial on the treason charges brought against him by Gen. Agha Mohammad Yahya Khan. President of Pakistan. The Government had announced that Sheikh Mujib was arrested at his home in Dacca early on March 26.

Since the army has clearly won the first stage of the war, the Bengalis are counting on the monsoon rains, which will begin in a few weeks, to give them an advantage.

The difficult countryside of East Pakistan-a veined network of the thousands of rivers and streams of the Ganges-Brahmaputra systems alien to the Punjabi and Pathan soldiers from the dry plains and mountains of the western province. When the monsoons swell the rivers and flood much of East Pakistan from May through October, it will become even more alien.

"We are just waiting for the monsoon," a Bengali officer said. "They are so frightened of water you can't imagine. And we are masters of water. They won't be able ~o move their artillery and tanks, and their planes won't be able to fly. Nature will be our second army."

The Bengalis are bitter about the failure of the United States to take a strong stand against the Pakistani Government; most of the leaders of the independence movement are pro-Western and were hoping for support from Washington. They are even more bitter about the American weapons being used against them.

"WE WERE EXPECTING HELP"

"Do you know, they are using your planes, your rockets, your tanks, to kill us?" a Bengali soldier, his voice tense and his eyes narrowed, asked the American correspondent. "We were expecting help, not this." Similar remarks were made repeatedly by others.

The Bengalis are not so surprised by the Chinese weapons the army is using because they apparently expected Peking to support the Government. Some Bengali officers, contending that the army offensive was worked out in advance with the Chinese, insist that the army would never have embarked on such a venture without assurances of full support from Peking

Even before the offensive, the Bengalis wondered why the Western powers and others did not support their cause. Now their disillusionment is complete.

"This is genocide, and people are just standing by and looking," a Bengali student remarked. "Nobody has spoken out. Has the world no conscience?"

The bitterness does not include India, which has condemned the Pakistani military action and is trying to persuade other governments to put pressure on Pakistan to stop the killing.

Indian civilians and officials in border areas are providing assistance to refugees and others, but this correspondent saw no arms being transported across the border-as the Pakistani Government has charged and New Delhi has repeatedly denied.

EVACUEES DESCRIBE ATROCITIES

Both refugees and Western evacuees have brought tales of atrocities and slaughter.

One Westerner, manager of a jute mill in the Chittagong area, said that while he hid from the army for three hours in a ditch, he saw troops bring a truck convoy down the road. in the lead truck, he said, were several Bengalis held at gunpoint and told to shout "Victory for Bengal," an independence slogan. When they did so other Bengalis came out of their hiding places and were machine-gunned.

"They want to drag us so far down that the nation will be back in the 18th century," a Bengali soldier said, "so that there will be famine and we will be reduced to eating grass. They want to make sure that no head will ever be raised against them again."

There have also been reports from scattered areas of the province that Bengalis were retaliating by killing West Pakistanis and other non-Bengalis, particularly businessmen.

But the killing of Bengalis, which has been systematic, was apparently planned long in advance. Members of the Muslim League, an ineffectual religiously oriented party in East Pakistan long associated with the army and other West Pakistani Interests, have been reportedly been assisting the army in ferreting out students and other potential leaders.

An engineer reached India yesterday with his wife and year-old son after walking for seven days from Dacca. The engineer, who had held a Government job, said that although he had not been a member of the Awami League and had not taken active part in the nationalist movement, he left because "it was systematic killing of the educated."

"If I had stayed," he said softly, "it would have meant death, certain death."