The 200 U.S. Marines sent as peacekeepers into war-ravaged Liberia have a limited mission and will be withdrawn by Oct. 1, President Bush said.

The Marines landed last Thursday, charged with aiding an eventual 3,250-person West African peace force meant to end 14 years of near-constant strife in Liberia.

"Their job is to help secure an airport and a port so food can be off-loaded and the delivery process begun to help people in Monrovia (search)," Bush said in an interview last week with Armed Forces Radio and Television Service in Miramar, Calif., where he was visiting with thousands of Marines, sailors and Coast Guard personnel. A transcript of the interview was released Monday.

"We'll be out of there by October the 1st," Bush said. "We've got U.N. blue helmeted troops ready to replace our limited number of troops."

The pledge to withdraw the U.S. troops was made public as the Liberian government and rebels signed a peace accord in Ghana to end a three-year insurgency that toppled warlord-president Charles Taylor (search). The accord calls for a two-year power-sharing government, meant to lead Liberia into elections and out of 14 years of conflict brought on by Taylor.

In the interview, Bush reiterated that America's role would be "short-term."

"We have a special obligation in Liberia to help with humanitarian aid. And, therefore, we will," Bush said. "And I said, secondly, we will have a limited mission, of limited duration and limited scope, and that we will help what's called ECOMIL (search), which is the Western African nations' militaries, go in and provide the conditions necessary for humanitarian aid to move."

On other international issues, Bush emphasized that the United States was committed to providing stability and security in Iraq, but that by the fall, some of the burden on U.S.-led troops would be lifted. A contingent of Polish troops is expected to be in Iraq around Sept. 4, and other nations will be going in to support the Polish and British troops.

"We're developing an Iraq police force, as well as an Iraqi army," Bush said in the interview. "And the idea is at some point in time the Iraqi army is able to secure the power lines and prevent the looting. ... This fall you'll see a lot of protective load, kind of the guarding role being taken off the shoulders of U.S. troops and shared by coalition forces."

In advance of negotiations with North Korea (search) next week in Beijing, Bush said he thought it will be difficult to convince North Korea's Kim Jong Il to give up his nuclear weapons program, but that he believes it can be done.

"I'd like to solve this diplomatically and I believe we can," he said. "It's going to take a lot of persuasion by countries besides the United States to convince him."

Negotiations over the communist state's nuclear pursuits are to be held between Pyongyang and the United States, South Korea, China, Japan and Russia.