WASHINGTON - The Pentagon is expected to send 3,500 troops into Kuwait to stand ready for use in Iraq, senior defense officials said on Tuesday as the Bush administration weighs adjusting force levels in the war.

The "call-forward" force was requested by Army Gen. John Abizaid, head of the military command responsible for the Middle East, and must be approved by Defense Secretary Robert Gates.

According to one official, Abizaid's request came before Gates' fact-finding trip last week to Iraq to assess possible alternative strategies in a war that he and President George W. Bush say America is not winning.

Options for changing course in the war include a short-term increase, or "surge," of 20,000 to 30,000 U.S. troops in Iraq. The US force level there now stands at 134,000.

"If we're going to surge, this makes sense," the official on Tuesday.

Gates questioned U.S. commanders last week about the possibility of a surge and what it might accomplish. He has given little hint of his thoughts on the concept, but said generals in the war zone worry an increase in US forces could allow Iraqis to delay taking responsibility for security.

"I think that any time that you look at adjusting the troop strengths, the coalition troop strengths, you have to consider the impact that that has on the populace, to the extent that it benefits the security situation and at the same time has a negative impact on the Iraqi people given that you are still an occupying force in a sovereign nation," said Pentagon spokesman Bryan Whitman about Gates' consideration of more troops.

"There's a tension there that you have to be cognizant of and finding the right balance is important and I think that's what our commanders have always emphasized and I'm sure that they relayed to the secretary in their discussions," Whitman said.

Another official, speaking on condition of anonymity, did not know if Gates had yet approved the deployment of the standby force, but said the announcement was expected as early as Wednesday.

The unit likely would come from Fort Bragg and fill a reserve slot that has been empty since commanders moved the previous call-forward force into the war zone earlier this year, that official said.

The troops could be in place in Kuwait by mid-January.