WASHINGTON - Congress is knocking nearly $1 billion off President Obama's request for Afghanistan's security forces and instead devoting the money to buying more mine-resistant vehicles for U.S. troops there.

The move comes as top House-Senate lawmakers are putting the finishing touches on a $626 billion Pentagon spending bill that Democratic leaders hope to clear for Obama's signature by Friday. Passage has been held up for weeks because Democratic leaders want to attach other, controversial items to it.

The measure contains $128 billion to support Obama's February request for military operations in Iraq and Afghanistan. Obama has yet to request funds for his recently announced troop increase in Afghanistan.

The package contains about $465 million to develop an alternative engine for the F-35 Joint Strike Fighter, the Air Force's multimission fighter of the future. It has no funds for new F-22 fighters. Defense Secretary Robert M. Gates staked his reputation on killing the jobs-rich but well-over-budget F-22 program, which is poorly suited for anti-insurgent battles in Iraq and Afghanistan.

The bill would trim $900 million from the Pentagon's $7.5 billion budget to train Afghan security forces. It would use the money to buy 1,400 additional mine-resistance vehicles suited for rugged conditions in Afghanistan.

Lawmakers said they support training Afghan soldiers - the linchpin in the U.S. strategy to end the war. But Senate Appropriations Committee Chairman Daniel K. Inouye (D., Hawaii) has said the Afghan government can't use all the money until 2011. Negotiators siphoned it for more armored vehicles.

It may take days for the measure to officially come together as House and Senate leaders grapple over what items to add to it. House Democrats want to attach an extension of jobless benefits and health-insurance subsidies for the unemployed - as well as a jobs bill containing new infrastructure money and other spending that the Senate is resisting.

Democratic leaders also hope the measure can carry a politically unpopular increase in the government's ability to issue U.S. debt.