It's a coalition of the dwindling. The U.S.-led multinational force in Iraq is losing two of its most important allies — Italy and South Korea — and up to half a dozen other members could draw down their forces or pull out entirely by the end of the year.

The withdrawals are complicating America's effort to begin extracting itself from the country, where a fresh onslaught of deadly attacks on coalition forces is testing the resolve of key partners such as Britain and Poland to stick with the mission despite the dangers.

Some observers say Iraq's deteriorating security situation is an argument for coalition forces to stay — not leave — and perhaps even deploy additional forces to help tamp down violence as Iraqi Prime Minister Nouri al-Maliki works to shift all security duties to Iraqis over the next 18 months.

Underscoring the reality, the Pentagon said Tuesday it is shifting about 1,500 U.S. troops from a reserve force in Kuwait to western Iraq's volatile Anbar province to help the Iraqis establish order there.

Increased instability, violence and radical Islamism in Iraq could require "a larger role for overt, coordinated, multilateral intervention, involving the key regional powers, to stabilize the situation," defense analyst Christopher Langton of the London-based International Institute of Strategic Studies warns in a new report, Military Balance 2006.

Defense Secretary Des Browne of Britain, the No. 2 military presence in Iraq with about 8,000 troops, conceded Tuesday that the latest string of attacks was "a major concern."

Two British soldiers were killed and two others wounded in a roadside bomb attack in Basra on Sunday, bringing to nine the number of British personnel who have died in the southern Iraqi city this month and pushing total British casualties since the war began three years ago to 113.

Despite the bloodshed, strong public opposition to Britain's involvement and recent reports that more than 1,000 British troops may have deserted since 2003, Browne insisted there were no plans to get out.

"We will continue to remain in Iraq until the Iraqi government is confident that the Iraqi security forces are capable of providing security without assistance from the coalition forces," he told the British Broadcasting Corp.

"That will, of course, be in consultation with us and our allies. But the decision on withdrawal will be based on achieving the right conditions but not on a particular timetable."

The United States still provides most of the muscle for the mission with about 132,000 troops.

Officials have said they would like that number reduced to about 100,000 by the end of 2006, although White House spokesman Tony Snow cautioned last week that U.S. President George W. Bush is unlikely to say "we're going to be out in one year, two years, four years."

The latest blow to the 26-nation coalition is Italy's decision to pull its remaining 2,600 troops out by the end of the year.

Italy's new defense minister, Arturo Parisi, was quoted by Italian media Tuesday as saying "Italy won't turn its back on Iraq" and would offer unspecified political, civil and humanitarian support.

Italian Foreign Minister Massimo D'Alema, meanwhile, wrote in Tuesday's Corriere della Sera newspaper that the pullout would be carried out "with the minimum possible risk for our soldiers, who have paid a high price," referring to the deaths of 31 Italian troops in Iraq.

"We'll be able to deal with this decision while keeping in mind the consequences for the Iraqi people and the need to coordinate with coalition forces," said D'Alema, confirming the force would be reduced to 1,600 by mid-June.

South Korea, the third-largest contributor of forces, began bringing troops home earlier this week as part of a plan to withdraw about 1,000 of its 3,200 soldiers in northern Iraq by the end of the year.

Lawmakers in Denmark, which has 530 personnel in Iraq, on Tuesday approved a government plan to cut the contingent by 80 troops and extended the mission to June 30, 2007.

Japan, which has about 600 non-combat troops doing humanitarian work in southern Iraq, has said it won't decide whether to withdraw them until Baghdad appoints new defense and interior ministers. There has been widespread speculation that the Japanese force will be pulled out this year.

Poland's prime minister, meanwhile, said earlier this month his government was still weighing whether to keep troops in Iraq beyond the end of 2006. Poland has 900 troops in central Iraq, where it leads an international force.