Some countries expressed concern about the whereabouts of Iraqi President Saddam Hussein and the lack of formal acknowledgement of defeat from his regime.

"The war is still going on. We wish that the people of Iraq will drop their guns and walk on the path to peace," Japan's Chief Cabinet Secretary Yasuo Fukuda told reporters.

"We hope this will end soon without an increase in the number of casualties," Fukuda said.

Fukuda did not specify what Tokyo would do to help rebuild Iraq, but he said that "as the number-two economy of the world, (Japan) should do what it can."

The Japanese foreign ministry announced Wednesday that Japan would donate up to 100 million dollars to international organisations in response to the United Nations appeal for immediate humanitarian assistance for the Iraqi people.

Australia's leaders, who have contributed a small military force to the US-led invasion, are now also tasked with defining their country's role in Iraq.

"There are difficulties ahead, the first difficulty is in effect to complete the war," Defense Minister Robert Hill said.

"There is still sporadic fighting within Baghdad, parts of the government sector of Baghdad haven't yet been taken on the ground, there's still fighting around Tikrit," he said, referring to the main city in Saddam's home region in northern Iraq.

Australia will join the United States and Britain in forming a transitional authority in Iraq, Prime Minister John Howard said.

"Australia has decided that this country will join the United States and the United Kingdom as partners in the coalition transitional authority in Iraq, which will be involved in overall administrative matters on the pathway towards transferring power in that country to the Iraqi people," Howard told reporters.

The fact that Iraq's interim government is not likely to have much input from the United Nations has angered some countries, who have accused the United States of strong-arming the world body, which opposed military action against Saddam.

"The UN should play a leading role, especially in the reconstruction of Iraq, with respect to how the post-war reconstruction should be arranged politically and economically," China's foreign ministry spokesman Liu Jianchao said Thursday.

"The Chinese government is very much concerned with the difficulties confronting the Iraqi people and will continue to provide humanitarian assistance to the Iraqi people," Liu said, adding that Saddam's regime had now collapsed and the United States was risking a "humanitarian disaster" with continued fighting.

His statements came as US military forces assaulted Baghdad's city center amid an extensive search for regime leaders.

Jakarta also urged the United States to give the UN a larger role in post-war Iraq, and called on the US-led coalition to keep its pre-war promises to the Iraqi people.

"The US should make true its word to free the people from the pressure of the regime in power and defend the interests of the Iraqi people themselves," Foreign Minister Hassan Wirayuda said.

Iraq's embassies in China, Thailand, Malaysia and Vietnam remained open Thursday, all saying they were awaiting further instructions from Baghdad.

A Thai-based diplomat said the US-led war in his country was over and that he hoped now for peace.

"We are waiting to watch the situation in Baghdad in the coming days," third secretary Talal Waleed told AFP.

But another diplomat remained defiant, saying the Iraqi people will keep fighting against the US-led coalition.

"The battle of the capital has not ended yet," said Salah Elmukhtar, Iraq's ambassador in Hanoi. "Iraqi people are all against the foreign invasion. If we lose Baghdad, we will keep fighting in other cities. It could last one month, one year, ten years."

SPACE.WIRE