Congressional leaders of both parties returned yesterday from a Thanksgiving Day visit to the Persian Gulf praising the morale of U.S. troops but insisting President Bush must seek the approval of Congress before sending those forces into combat against the Iraqi occupation of Kuwait.

Senate Majority Leader George J. Mitchell (D-Maine), who made the trip at Bush's invitation along with Minority Leader Robert J. Dole (R-Kan.), House Speaker Thomas S. Foley (D-Wash.) and Minority Leader Robert H. Michel (R-Ill.), also criticized Bush's meeting in Geneva yesterday with Syrian President Hafez Assad, who has committed 15,000 troops to the gulf as part of the multinational force arrayed against Iraqi President Saddam Hussein.

Mitchell called the meeting "ill-advised" and "an unnecessary step," noting that the United States has officially identified Syria as a nation sponsoring and condoning terrorism. Dole said, "I think we need to be careful in our meetings" with Assad, but that "we seem to be on the same side" in opposing Saddam.

The four held a news conference and a series of television interviews after flying home from Saudi Arabia, where they accompanied President Bush and his wife at four meetings with U.S. ground and naval detachments. The ostensible purpose of the trip was to demonstrate to the largest fighting force the United States has assembled since the Vietnam War that the government is fully united in supporting the gulf effort.

Some observers suggested that in inviting the congressional leadership, Bush also wanted to slow down the second-guessing of his Persian Gulf policy, which began in earnest on Capitol Hill after this month's elections. Although a move to recall Congress to debate gulf policy appears to have been set aside, a series of congressional hearings on the subject is scheduled to begin Tuesday.

As before their trip, the returning leaders flashed a bipartisan caution light to Bush against ordering offensive action against the Iraqi forces without specific prior approval by Congress.

Mitchell said he supported the president's decision to deploy forces in the gulf and added, in an interview with Cable News Network, "Obviously, our forces, as all forces, have the right of self-defense, the right to respond to any emergency. But a planned military offensive, which is, by definition, an act of war, must receive the prior authorization of the Congress."

Dole, agreeing, said he hoped that if the United States gains enough support in the United Nations Security Council to pass a resolution "which authorizes the use of force, if necessary," to drive the Iraqis out of Kuwait, "then I would hope Congress would reconvene and take similar action."

Foley said he agreed that "if such a decision is taken, I think . . . it would be incumbent on the president to seek the approval of Congress. But, so far, I don't think the president has changed that policy."

Mitchell and Dole both said Bush had reiterated that, for now, the United States is still relying on U.N. economic sanctions to force Saddam to rethink his Aug. 2 invasion and subsequent annexation of Kuwait. But Dole said that a policy change could be imminent.

"I would keep my eye on the Americans in the embassy in Kuwait," he said. "In my view, that's going to be the next flashpoint. If they run out of food and {we} aren't able to resupply the embassy . . . then I'm not certain what may happen."

There have been conflicting reports about conditions affecting the 27 people, including eight U.S. diplomats, who have remained in the embassy in Kuwait City despite Iraqi orders to close down the building.

In the same interview, Dole said he thought American domestic opinion would force some sort of early showdown with Saddam. "I think the American people are very understanding," he said, "but we also tend to be impatient. We want things to happen. We don't want a war, we want it to end peaceably, but we don't want to wait too long."

All four congressional leaders said they were impressed by the spirit and commitment of the U.S. troops, who now total about 230,000 land, air and sea forces in the gulf area. Foley said in a Fox Broadcasting interview that the troops "are doing a terrific job. . . . We came away, really, with . . . some sense of encouragement and satisfaction."

Mitchell said he "was impressed with their high spirit, their morale, their intelligence," adding that "they appear to be well-trained, well-equipped and well-motivated."

Dole said, "It was a morale booster for us to see all these bright young men and women and the high spirits." Michel said, "Obviously they have that apprehension as to what comes next, but there's a high degree of discipline and morale, I thought, was fine."