South Korea has cancelled a plan to send troops to the northern Iraqi city of Kirkuk next month, saying it is concerned about security in the area.
South Korea was to have the third largest foreign contingent in Iraq
The Seoul government says it still intends to send soldiers to Iraq but is looking for a different location.
South Korea was preparing to send more than 3,000 troops - which would have made it the third largest contributor to the multinational force.
Spain says it will pull out its own troops unless the UN takes charge.
Despite an appeal from US President George Bush, Prime Minister-elect Jose Luis Rodriguez Zapatero said he would recall Spain's 1,300 troops by the end of June.
In Poland, President Aleksander Kwasniewski says his country was misled about the alleged threat from Iraqi weapons of mass destruction.
However, he also defended the decision to go to war in Iraq and said he had no plans to withdraw Polish soldiers.
Poland was a strong supporter of the US-led invasion and has the fourth largest contingent of occupying troops.
The remarks came a week after the Madrid bombings and as public support for Poland's role in Iraq is declining.
"Of course I feel a certain discomfort that we were misled about weapons of mass destruction," Mr Kwasniewski told journalists on Thursday.
He refused to point the finger of blame at either the US or the UK, and insisted the decision to go to war had been the right one.
"Iraq today, without Saddam Hussein, is a much better place than Iraq with Saddam Hussein," the Polish president said.
Poland has been one of Washington's staunchest allies on Iraq.
Warsaw contributed combat troops to the invasion and now commands a 9,500-strong multinational force in central Iraq.
The deployment was controversial in South Korea.
The defence ministry cancelled the move because of concerns that troops would have to participate in offensive operations.
Press reports say the US was planning to lead combat troops near Kirkuk.
The South Korean government says it wants to take part in peaceful reconstruction and keep operational command in its own area.
In a statement, the defence ministry said: "The United States and South Korea have agreed that it is inevitable to change the location for South Korean troops as the security situation in Kirkuk has become worse.
"The two countries agreed to reconsider a possible location putting the whole of Iraq under review."
The deployment to a new location is now expected by June.
Washington had initially hoped South Korea would send a larger, combat-ready contingent.
But faced with domestic criticism of the war, the Seoul government insisted its troops should focus on reconstruction and relief work.
Acting South Korean President Goh Kun has warned that the country could become a target for terrorist attacks because of its involvement in Iraq.