SEOUL, South Korea — South Korea announced plans today to pull a third of its troops out of Iraq, a day after President Bush met with South Korea's leader and praised him as a staunch ally in the Iraq conflict.

About 3,200 South Korean troops are stationed in northern Iraq, the third-largest contingent in the coalition after the United States and Britain.

South Korea's move caught the White House by surprise. "They have not informed the United States government of that," said National Security Council spokesman Frederick Jones.

Jones said South Korean President Roh Moo-hyun did not raise the subject of troop withdrawals with Bush when they met Thursday in the South Korean city of Gyeongju.

During the meeting Bush thanked Roh for the Korean contribution, saying its goal was to "help democracy flourish."

Defense Minister Yoon Kwang-ung reported the plan to withdraw about 1,000 troops from Iraq to the ruling Uri Party today, the ministry said.

The defense ministry said it plans to include the troop reduction plan when it seeks parliamentary approval for extending the deployment in Iraq, as it is required to do each year. It did not say whether Seoul had consulted Washington on the plan.

The troop dispatch has been unpopular among South Koreans. Many consider the U.S.-led war in Iraq unjustified, and the government had to overcome protests from activists in accepting U.S. requests for troops.

There have been previous calls for reducing South Korea's troop presence in the Gulf state.

In September, ruling party lawmaker Rep. Kim Sung-gon said about 1,000 troops should be withdrawn from Iraq "considering the worsening public sentiment about the troop dispatch."

At the time, the ministry dismissed the comment, saying it was nothing but a proposal presented by one lawmaker.