U.S. lawmakers are promising close scrutiny of the Bush administration's request to divert hundreds of millions of dollars in anti-terrorism aid to upgrade Pakistan's aging fleet of U.S.-made F-16 fighter planes.

The Bush administration says the upgraded F-16s will allow Pakistan to better conduct precision attacks on terrorists. But the planes have not traditionally been used in anti-terrorism operations. Pakistan sees them as an asset in its arms race against rival India.

Democratic Rep. Gary Ackerman says updating the F-16s may not be the best way to fight extremists.

The comments came as a Pakistan army spokesman said the military has ordered its forces to open fire if U.S. troops launch another air or ground raid across the Afghan border.