Retired Gen. Tommy Franks (search) said Thursday he doesn't know how long U.S. troops will remain in Iraq, whether it is one year, two years, four years or some other stretch.

"We want to be there as long as it takes to enable the Iraqis to have the governance" they need, said Franks, who headed Operation Iraqi Freedom (search) until last week when he retired from the military after a 36-year career. "But we don't want to be there a day longer."

Speaking to the House Armed Services Committee (search), Franks said the 148,000 troops on the ground will probably be there for at least one year. To aid the U.S. troops, 18 other countries have forces in Iraq, another 19 are preparing to send troops and 11 are discussing it.

More than 70 U.S. troops have died since May 1, after major combat ended. Franks said that on any given day, U.S. troops will face between 10 and 25 attacks, especially in the areas in and around Baghdad.

On a five-day trip to Africa, Bush responded to concern about the rising death toll, saying, "There's no question we have a security issue in Iraq, and we've just got to deal with it person to person. We're going to have to remain tough."

In the last 24 hours, two more U.S. soldiers were killed in separate attacks. Franks reminded the committee that just because major combat has ended, peace has not yet arrived.

"I think it's very important for us to all remember and continue to remind ourselves that the term 'stability operations', which is what we're doing right now, does not infer that 'combat operations' have ended," he said. "It does infer that major combat operations against enemy formations have ended. Military forces are still required to set conditions that will enable the evolution of Iraq."

Franks said the United States is committed to helping Iraq build the infrastructure it needs for a peaceful and democratic society, including early humanitarian aid, formation and training of police and security forces, as well as an Iraqi army, and local and national government.

Bush said the people of Iraq are still not accustomed to their freedom and need a little time to get used to it and realize they can drop their guns.

"It's going take more than 90 to 100 days for people to recognize the great joys of freedom and the responsibilities that come with freedom," he said. "It's very important for us to stay the course, and we will stay the course."

On Capitol Hill, Rep. Ike Skelton, D-Mo., the senior Democrat on the House Armed Services Committee, said he thinks the Defense Department didn't prepare adequately for post-combat operations, and he told Franks that he fears "we may find ourselves in the throes of guerrilla warfare for years."

"We cannot leave Iraq," Skelton said. "This must be a success."

Franks agreed that "absolute success" is the only measure by which to determine when to exit the country. He added that quick governance and economic stability will allow that outcome to be "sooner rather than later" and that violence will continue "until we are able to root out the Baathists, the jihadists."

Without that, "it will take longer, but the outcome will be the same."

Franks said he could not determine if Saddam Hussein is alive and has frequently vacillated on his fate, but said that as soon as it is confirmed he is dead, people will be much quicker to accept changes in Iraq.

Fox News' Bret Baier and the Associated Press contributed to this report.