The number of U.S. troops in Iraq probably won't decline significantly from the current 148,000 until sometime next year, Gen. Tommy Franks said Thursday. The kinds of hit-and-run attacks that killed two American soldiers Wednesday will continue, he warned.

"We need to not develop an expectation that all of these difficulties will go away in one month or two months or three months," Franks told the House Armed Services Committee.

"I anticipate we'll be involved in Iraq in the future," Franks added later. "Whether that means two years or four years, I don't know."

Congressional critics kept up their questioning of the administration's justifications for going to war and its characterizations of the current outlook in Iraq.

Ike Skelton of Missouri, said he worried "we may find ourselves in the throes of guerrilla warfare for years." More than 70 American soldiers have died since Bush declared major combat over May 1.

Much of the criticism has focused on Bush's main justification for the war -- that Saddam Hussein's government had chemical and biological weapons and was working to build more of them and develop nuclear bombs. No such weapons have been found in Iraq.