Rajshahi, PAKISTAN.-The crushing force of West Pakistan's military operation against the Bengali separatists has apparently destroyed all serious armed opposition in East Pakistan.

Rajshahi, a city that used to have a population of 100,000, stands on the east bank of the muddy sluggish Ganges River, with India visible on the opposite shore 3,000 yards away. Border towns like this were political strongholds of the now-banned separatist Awami League, which won a sweeping victory in the national legislative election Dec. 7. The National army, made up mostly of Punjabis from West Pakistan, struck against the separatists throughout East Pakistan on March 25.

By mid-April, apparently, the army's campaign was virtually completed. The last-ditch opposition the army met in border regions was squelched swiftly and although army patrols still draw occasional sniper fire, the eastern wing seems firmly under control.

VAST DESTRUCTION

The cost for all concerned has been agony. Newsmen have seen tens of thousands of leveled or gutted buildings. In the towns concrete walls pocked by hundreds of bullets where firing squads did their work, human bodies dumped into community wells and desolation testify to the ferocity of events.

Precisely how it all happened is not apparent because testimony is totally conflicting, depending on the point of view of the witness. The army and civilian peace committees established throughout the eastern wing say that the bulk of ,the destruction and slaughter was perpetrated by the rebels or Indian troops who, they charge, infiltrated across the border. But newsmen often are approached by Bengalis who slip up to whisper a few words before darting out of the sight of the ever- present peace committeemen.

Don't believe what they're telling you," one said. "They did it all. We are oppressed and cannot tell you what happened."

Most of the peace committee members, to whom the army has delegated a certain measure of civil administration, are Moslem Biharis who came from predominantly Hindu India to Pakistan when the nation came into existence in 1947.

Business and trade in East Pakistan in largely in the hands of Biharis, who are a small minority among ,the local Bengalis. The latter was mostly Moslems, but there is a substantial Hindu minority.

Resentment on the part of many impoverished Bengalis toward the somewhat more prosperous Biharis was a factor in the Bengali separatist movement in the recent war. The impression, based on the testimony of hundreds of witnesses is that what seemed that the Awami League WAS about to come to power, Bengalis in some communities looted, and burned Bihari houses and slaughtered their occupants,

The Bengalis in the national army revolted to join the separatists. When the predominantly Punjabi army of West Pakistan smashed its way into the eastern wing it had ready allies among the minority Biharis, most of whom were burning for revenge.

BENGALIS FLEE CITIES

The magnitude of the killing that followed has sickened most observers. As a result of the violence, a majority of the Bengalis and nearly all of the large Hindu minority in towns like this have fled. Here, the block of buildings making up the main market area of the city lies smashed, apparently by mortar fire from army units that book the town April 14.

Some five-story buildings with ornately decorated wooden balconies in the area still stand, but sometimes with their upper floors in ruins as the result of shelling. But much of the city is untouched by shellfire, and bicycle rickshaws and street vendors have begun to ply the streets. The town again has water, electricity, communications, and even a complaint bureau.