"I expect to act fully as secretary of state until I do leave,"Powell said. "I will be working hard until the very, very end," Powell told a news conference.

Powell, 67, submitted his letter of resignation to President George W. Bush on Friday. He told the news conference that "it had always been my intention to serve one term."

Speaking of American diplomacy, Powell said that the war on terror remains on the top priority which is followed by consolidating the new democracy in Afghanistan and stabilizing Iraq after the US-led invasion to oust Saddam Hussein last year.

"We had some difficulties with some nations in Europe last yearover Iraq, and we are getting rid of those differences and coming together again, as evidenced by the fact NATO is now undertaking amission in support of the Iraqi people," he said.

Powell also stressed to beef up efforts to restart the Middle East peace process after the death of Palestinian leader Yasser Arafat, and to solve nuclear issues in the Democratic People's Republic of Korea and Iran.

The White House confirmed Powell's resignation, but declined tosay whom Bush was considering as a replacement. Scott McClellan, spokesman of the White House, said Powell would stay on until his successor was in place.

Powell was often seen representing more moderate views on foreign policy in the Bush administration.

Observers said that Powell's leave will deprive the Bush administration of probably its most respected member abroad at a time when Bush is trying to mend fences with allies damaged by the Iraq war and revive the Middle East peace process.

However, Powell denied that his decision of resignation would affect his ability to pursue the agenda in the coming weeks, saying he was still secretary of state operating with Bush's authority.

Powell is scheduled to meet later Monday with Israeli Foreign Minister Silvan Shalom and was to attend a meeting of Asian officials in Chile Wednesday and a multinational conference on Iraq next week.