The State Department acknowledged yesterday that two shiploads of U.S. military equipment were being sent to Pakistan but said this was not in violation of an official ban on weapons sales.

State Department spokesman Charles Bray said Pakistan purchased the arms before the ban went into effect on March 25.

The spokesman added that the sales were made under a long-term understanding that the equipment be used only for defense purpose by the Pakistanis. If it were used to put down the bloody independence movement in East Pakistan this would cause consternation to the United States, he said.

The State Department has already acknowledged that Pakistan was using earlier U.S.-supplied tanks and Jet planes to put down the rebellion.

The Assistant Secretary of State for Congressional Relations, David M. Abshire last month told a group of U.S. senators that Pakistan was under no obligation to consult with Washington on the transfer of weapons from one part of the country to another. He added that the American weapons were being used in the eastern wing of the country despite secret diplomatic pressures from the United States.

The State Department has frequently said that "no military items have been provided to the government of Pakistan or its agents since the outbreak of fighting in East Pakistan March 25 and nothing is now scheduled for such delivery."

In its Tuesday edition, The New York Times said one Pakistani vessel-the Sunderbans sailed from New York on May 8 with military equipment, including parts for armed personnel carriers. The newspaper also reported that another ship, the Padma, was preparing to leave for Pakistan bearing eight U.S. military planes, 113 parachutes and mechanical snare parts sold to Pakistan by the U.S. under the Foreign Military Sales Act .