Secretary of Defense Richard B. Cheney yesterday backed away from a previous statement that U.S. forces in the Middle East would not be rotated back home until Iraq has withdrawn from Kuwait, telling congressional critics that the issue remains undecided, according to several legislators.

Cheney provided the new statement after House Armed Services Committee Chairman Les Aspin (D-Wis.) and other legislators said during a closed meeting on Capitol Hill that the absence of any troop-rotation plan appeared to foreclose the option of a peaceful settlement of the crisis and render war more likely, the sources said.

Cheney responded that no decision has been made because many troops have not yet arrived, making any assessment of the military situation there premature, according to legislators who were at the afternoon meeting.

They said Cheney also said the decision could be postponed because those deployed to the region in August would in any event not be eligible for rotation home until early next year, when they had served for at least six months.

"The fact that there is no rotation policy does not mean there will be no rotation," Aspin quoted Cheney and Joint Chiefs of Staff Chairman Gen. Colin L. Powell as saying after a two-hour briefing for the House Armed Services Committee. "We have not made a final decision on rotation."

On Friday, however, Cheney had announced that U.S. forces deployed in the gulf would remain for the duration of the crisis.

Aspin said he told Cheney and Powell that a "no-rotation policy would mean you have eliminated the option of waiting to see if the {economic} embargo {of Iraq} will work. Somehow, this thing would have to come to a head within a year and that may be before the embargo has an opportunity to work."

Cheney's new statement, latest in a series of shifts in the administration's military plans for the Middle East, came as the Pentagon authorized an additional call-up of Navy reservists for service in the Persian Gulf, and as officials disclosed U.S. plans to conduct the first landing exercise by Marines on Saudi beaches south of Kuwait Thursday.

The moves followed the administration's decision last week to deploy up to 200,000 additional troops to the region in coming months in what officials described as an effort to threaten offensive military action in order to demonstrate U.S. resolve.

Asked about troop rotations, Pentagon spokesman Pete Williams said at a briefing yesterday that no such plans have been "announced," and that the issue was still being studied. He said the additional U.S. forces committed to the region last week would augment, not replace, the 230,000 troops now in the region. "At some point, possibly," this decision might be reconsidered, Williams said.

Defense officials and legislators said the differing remarks were prompted by the administration's desire to send two messages: one reinforcing the possibility of military action if Iraqi President Saddam Hussein does not withdraw his forces from Kuwait; the other leaving open the possibility that the crisis can be resolved without a U.S. and allied military offensive.

House and Senate legislators from both political parties repeatedly cautioned Cheney and Powell yesterday against precipitous military action, and urged that the economic embargo of Iraq be given more time to work, according to several lawmakers.

"I don't think anybody wants" combat to occur before it is necessary, said Rep. John R. Kasich (R-Ohio), who heard the presentation by Cheney and Powell.

"To the extent that we can inject flexibility into the process, {it is all} the better," said Sen. John W. Warner (Va.), senior Republican on the Armed Services Committee, who met with Cheney and Powell at breakfast. Warner said he continues to believe that the crisis can be resolved "without conflict."

Sen. Sam Nunn (D-Ga.), the committee chairman, said he and Warner pressed the two officials on the need for other countries to provide more ground forces in the gulf to bolster the image of multinational opposition to Iraq's invasion.

While declining to provide details of the Marine landing exercise on the Saudi coast south of Kuwait, Williams said it was not intended to be provocative. "This is Saudi sovereign territory. It isn't like parts of the country have already been red-lined away."

Officials said the exercise would involve only a single Marine expeditionary unit of about 2,000 troops, unlike two other practice amphibious landing operations involving more than 10,000 Marines on the beaches of Oman in recent weeks. But it will be the first involving U.S. Air Force planes in addition to Marine helicopters.

Although the location of the exercise is classified, one official said it would be "tens of miles" south of the Kuwaiti border, placing it outside the range of Iraqi Silkworm surface-to-surface missiles.

Staff writer John E. Yang contributed to this report.