WASHINGTON, June 22—A spokesman for Senator Edward M. Kennedy said today the State Department had in formed the Senator that two freighters now sailing from New York to Karachi were carrying ammunition for the Pakistani armed forces.

The spokesman said the Massachusetts Democrat had been advised by a ranking State Department official that the Pakistani freighter Sunderbans, due in Karachi tomorrow, carried munitions and other military equipment sold to Pakistan under the United States foreign military sales program as well as through commercial suppliers.

Mr. Kennedy was told, the spokesmen said, that the Padma, another Pakistani freighter, which left New York this after noon, carried munitions along with spare parts and other items for military use that had been bought commercially by Pakistan and licensed for ex port by the State Department.

Senator Frank Church, Democrat of Idaho, urged President Nixon in a letter to order the Coast Guard to intercept the Padma to prevent the delivery of military equipment to Pakistan.

He said that if this could not be accomplished, the United States should seek Canada's co operation in halting the ship. The Padma's first scheduled port of call is Montreal.

Investigation Started

The State Department re fused to comment on Senator Kennedy's report. A spokesman said, “We do not know what there is aboard the ship” and announced that the State Department and the Bureau of Customs had begun a joint investigation to determine the nature of the Padma's cargo.

Secretary of Defense Melvin R. Laird told a Senate Appropriations subcommittee that “much of the information” published in The New York Times today on the shipments of military equipment to Pakistan was “false.”

Questioned by Senator William Proxmire, Democrat of Wisconsin, Mr. Laird said he was still “checking out” The Times report that eight aircraft had been shipped on the Padma.

The Times reported that air craft were included in the list of equipment delivered on May 25 on the dock in New York for loading aboard the Padma. A Defense Department spokes man said earlier today that no aircraft had been shipped, but a State Department spokesman said he could not be positive because “we do not know” what the Padma was carrying.

Sale by Air Force Denied

Mr. Laird said he wished to “contradict” the report that the equipment for Pakistan had been sold by the Air Force under the military sales program, but said that it might have been shipped under commercial license.

A State Department spokes man, Charles W. Bray 3d, said “it is possible” that equipment purchased under the military sales program and turned over to the Government of Pakistan in the United States before March 25 was aboard the Padma.

Mr. Bray took the view that the shipments aboard the Sunderbans and the Padma did not constitute a specific violation of the Administration's ban on deliveries of military equipment to Pakistan imposed after the Pakistan Government moved to crush the self‐rule movement in East Pakistan with repressive troop action beginning on March 25.

He said that the interruption of the military sales program for Pakistan and the licensing of commercially purchased equipment on the State Department's munition controls list had been made effective after March 25 and did not affect earlier transactions.

Decision Announced in April

Mr. Bray acknowledged un der questioning, however, that this technicality was not mentioned when the State Department made its formal announcement on April 15 concerning restrictions on military shipments to Pakistan.

The April 15 announcement said, in part: “We have been informed by the Department of Defense that none of these items [so‐called “nonlethal” military equipment and am munition] has been provided to the Pakistan Government or its agents since March 25 and nothing is now scheduled for such delivery. In short, no arms have been provided to the Government of Pakistan since the beginning or this crisis and the question of deliveries will be kept under review in the light of developments.”

When he was asked how this statement could be reconciled with the department's acknowledgment that military equipment may be aboard the two freighters, Mr. Bray said that the determining factor was whether such items had been turned over to Pakistani officials on United States territory before March 25.

In a speech on the Senate floor today, Mr. Kennedy said that “since very early in April, I have been assured repeatedly — in private conversations and official correspondence — that our Government was not supplying arms to Pakistan.