Australia has observed a day of national mourning in memory of the victims of the bombing on the Indonesian island of Bali last week.

More than 180 people were killed - over half of them Australian.

Flags flew at half-mast and church services and civic ceremonies were held around the country.

I don't want to sound alarmist but we are living in a different world

Prime Minister John Howard

A minute of silence was held at noon (0200 GMT) across the nation after which church and town hall bells tolled for a further minute.

As night fell, about 5,000 people attended a candlelit ceremony on a sporting ground in the city of Perth.

Many wreaths were laid in memory of victims

The ceremony marked the last of dozens of tributes held throughout the country on Sunday.

Prime Minister John Howard said before attending a church service in Canberra that the world had changed after Bali.

"I don't want to sound alarmist but we are living in a different world," he said.

"I can't give a guarantee it won't happen here."

Lost friends

Sydney held a huge memorial service in a park by the harbour, at which the singer Wendy Matthews performed her award-winning song, The Day You Went Away.

One suburb of the city, Coogee, remembered six members of its rugby team killed in the bombing.

"Last weekend, eleven of us went to Bali on a football trip," Erik De Hart, a survivor from the team, told the mourners.

Australians around the world - including the touring cricket team - have honoured the victims

"We were having a great time, and then hell happened."

Many people in Coogee, and up and down the country, were wearing a sprig of wattle - the country's national flower.

The UK flew flags at half-mast at home and at its diplomatic missions across the world on Sunday as a mark of respect.

President Bush offered his nation's solidarity with Australia in a videotaped message to the Australian people.

He promised to help hunt down those responsible for planting the bombs outside the packed Sari Club in Kuta Beach one week ago.

We send our prayers to the families who cry, and we send our prayers for a speedy recovery for the injured

George W Bush

"Together we face an enemy which does not value innocent life, an enemy which tries to terrorise the free world into inaction. They will fail."

The US and Australia are both among Western countries which have advised their citizens to leave Indonesia, fearful of more attacks.

Anti-terror drive

Indonesia - under fire from the US among others for not taking strong enough anti-terrorist measures before the Bali attack - has now enacted tough new decrees.

Foreign intelligence agents have also been sent to Indonesia to try to help track down those responsible, whom some say are linked to Osama Bin Laden's al-Qaeda which is blamed for the 11 September attacks.

On Saturday, Indonesian police arrested radical Muslim cleric Abu Bakar Ba'asyir in connection with earlier attacks on churches.

Some governments accuse Mr Ba'asyir of leading the Jemaah Islamiah group which Indonesia says has links to al-Qaeda, but he has denied this.