President Bush's “coalition of the willing” is set to all but disappear from Iraq by the end of the year, with 13 countries, including South Korea, Japan, Moldova and Tonga preparing to withdraw their few remaining troops.

Britain, Australia, Romania, Estonia and El Salvador are the only nations, apart from the US, that plan to remain after a UN mandate authorising their presence expires on December 31.

London must still reach an agreement with Baghdad, however, to keep its 4,100-strong contingent on the ground into the new year. Failure to do so in time would leave British troops without legal cover and they too would have to leave.

“We are going to say farewell to 13 different nations in the space of two and a half weeks,” said Brigadier-General Nicolas Matern, a deputy commander for Multi-National Corps Iraq, which oversees the US military's coalition partners.

“We started off with 35 countries but it has steadily been going down ... As from December it is going to go all the way down,” he told The Times.

A farewell ceremony took place on Wednesday for 76 Macedonian soldiers. Another is due today for 86 troops from Bosnia and Herzegovina and a third is scheduled for South Korea's contingent tomorrow. Others set to follow suit include soldiers from Albania, Azerbaijan, the Czech Republic, Denmark, Lithuania and Ukraine.

President Bush and Tony Blair scrambled the coalition together in the build-up to the Iraq invasion in a bid to put an international face on what was fast becoming an unpopular war. But the list of participants drew scorn for failing to include a greater number of powerful states, with the US and Britain the main contributors.

The size of the outgoing contingents ranges from just 4 Lithuanians to 300 South Koreans. Many countries have reduced their presence over the past five years, but it has always been a fraction of the US deployment, now standing at 146,000.

Bulgaria - with only 150 troops left in Iraq - has had forces south of Baghdad since June 2003, taking part in various operations, including patrols and guard duty. Thirteen Bulgarian soldiers have been killed and 81 injured in that time.

Lieutenant Colonel Valeri Kolev Valchanov said: “I think we have contributed somehow towards the stabilisation of the country.”

Bulgaria's troops are also preparing to pull out next month, a move that triggers mixed emotions for the Bulgarian officer. “I will never forget my friendships with Romanian soldiers, Ukrainian soldiers, Polish soldiers, American soldiers,” he said. “We were in dangerous conditions together and celebrated good moments together.”

Major Mario Ernesto Argueta is from El Salvador, which has 200 troops working on humanitarian projects in Wasit province, south of the Iraqi capital. He too believes that the efforts of a tiny contingent make an impact.

“It doesn't matter how many we are, the most important part is that you made a difference, not for the whole country but for the person who got the aid,” he said.

El Salvador is one of four coalition countries - excluding the United States and Britain - which have been invited to stay in Iraq beyond the end of the year.

“The US approached the Government of Iraq asking that we consider asking a few countries other than the United Kingdom to continue to provide some specialist forces for non-combat tasks after 31 December,” said Mowaffak al-Rubaie, Iraq's National Security Adviser. “After considering the request, the Prime Minister agreed and those countries were invited to continue to assist us.”

Formal agreements will be made with El Salvador, Australia, Romania and Estonia once a long-awaited security pact with the United States, which was approved by Parliament on Thursday, becomes law.

Outside the coalition, the North Atlantic Treaty Organisation, which has 200 troops from 15 countries in Iraq, is also trying to finalise an accord with Baghdad to continue a training mission in the country beyond the end of 2008.

In addition, the United Nations has a number of Fijian troops working in Iraq.

While the coalition is dissolving, another force of foreigners is still thriving in the country: thousands of private contractors from developing countries such as Peru, Uganda, the Philippines and Bangladesh.

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