Leaders of the Senate Foreign Relations Committee said yesterday that the War Powers Act, which requires congressional authorization for prolonged U.S. military involvement in hostile situations, was not overturned by last week's Supreme Court ruling that congressional vetoes are unconstitutional.

Chairman Charles H. Percy (R-Ill.) and Sen. Claiborne Pell (D-R.I.), the committee's ranking minority member, said in a joint statement that they do not believe the 1973 law has been rendered invalid.

It obliges the president to obtain congressional approval to keep U.S. troops abroad in hostile circumstances for more than 60 days.

"The basic feature of the War Powers Act survives: its requirement for congressional authorization of any prolonged U.S. military involvement in hostilities," Percy and Pell said.

Committee staff sources said the two senators, who based their statement on an opinion from the committee's legal counsel, conceded that the court decision removes the provision under which the House and Senate could order the president to remove forces from such a situation after 60 days.

But, they added, it is the committee's view that the law's basic requirement of seeking permission within that time frame does not constitute a legislative veto. They added, however, that the means Congress might have for forcing the president to comply are unclear.

The legality of the act, adopted by Congress as a potential brake on presidential actions during the Vietnam war, could lead to considerable contention in any disputes between Congress and the White House over use of U.S. forces in future foreign crises. Prior to the Supreme Court decision, for example, there had been speculation about whether the law would be applicable to such situations as expansion of the U.S. Marine force in Lebanon or a decision to send U.S. combat troops to El Salvador.

Congress allowed the original dispatch of Marines to join an international peace-keeping force in Lebanon without invoking the law, and the administration has insisted that it has no plans to involve U.S. forces in the Salvadoran civil war.

The Supreme Court ruled last Thursday that legislative-veto powers written into laws delegating decision-making authority to federal agencies are an unconstitutional intrusion on the executive branch's powers.

The decision affects about 200 laws in which Congress had sought to reserve power, by vote of one or both chambers, to block an executive-branch action. The immediate effect of the court's action on these laws is uncertain and is being studied throughout the government.

Percy and Pell acknowledged that the decision "raises fundamental questions about the relationship between Congress and the president." They said the committee is studying "the possible need for revisions in existing statutes to preserve a workable balance of constitutional authority between the branches."

"We will do our utmost to see that such actions are conducted in a completely bipartisan fashion and with due consideration for the important constitutional responsibilities of both branches of government," they added.