Many Australians are furious about their country's involvement

Indonesia, scene of last October's terrorist bombing on Bali, has increased security at US and other embassies as well as at shopping malls and other locations.

In the Philippines, President Gloria Arroyo called for "complete and total vigilance" against what she said were "extremists likely to attack in desperation anywhere and in any manner".

Governments were also braced for domestic protests, as thousands of people took to the streets to demonstrate against military action in Iraq.

Public anger was particularly acute in Australia, which has committed 2,000 troops to the war, and in Indonesia, the world's most populous Muslim nation.

There were large demonstrations in the Australian cities of Sydney, Melbourne and Canberra.

Police in Melbourne reported a crowd of "tens of thousands" of demonstrators, and one woman was arrested for splashing red paint on the US consulate there.

'Halt the war'

In the Indonesian capital of Jakarta, the BBC's Rachel Harvey says the protests, although peaceful, saw 3,000 people demonstrating outside the US embassy.

She says most of the protesters were supporters of the Muslim Justice Party, and some carried placards denouncing US President George Bush as "The World's Number One Terrorist."

There were reports of injuries after clashes between police and demonstrators in the central Javanese capital of Semerang.

Indonesian President Megawati Sukarnoputri issued a statement saying "Indonesia strongly denounces the unilateral attack on Iraq," and calling for an emergency meeting of the UN Security Council to urge a halt to the war.

The Australian Ambassador to Jakarta, David Richie, said that he was worried that radical groups could use the war as an excuse for violence.

"There is always a risk in this country of terrorism and violence," he told the BBC's East Asia Today programme.

"Our travel advisory urges all Australians to be immensely cautious in Indonesia."

Australian Prime Minister John Howard defended his decision to join the war in a nationally televised address.

Mr Howard reiterated his earlier arguments that support for military action was in Australia's national interest, arguing that the threat from Iraq was "direct, lethal and undeniable".

Despite Mr Howard's stance, the Australia's legislature remains divided.

The House of Representatives supports the war, while the Senate opposes it.

Australian armed police deployed around parliament in Canberra and increased their presence at US diplomatic missions.

Several Australian states mobilised 24-hour operations centres to cope with any incidents and put their rapid response units on standby.

In South Korea, scuffles were reported as about 2,000 activists demonstrated near the US embassy in Seoul.

South Korea's military has been placed on heightened alert for a possible escalation of nuclear brinkmanship by the North while the US' attention is trained on Iraq.

Japanese media have reported that the North is preparing to test-fire a ballistic missile.

Analysts believe North Korea will continue its pattern of provocation, both as a means to extract concessions from the US and as its fears grow that it may be Washington's next target.