BAGHDAD — Iraq's Cabinet overwhelmingly approved a security pact with the United States on Sunday, ending prolonged negotiations to allow American forces to remain for three more years in the country they first occupied in 2003.

The deal detailing the conditions of the U.S. presence still needs parliamentary approval, and lawmakers could vote as soon as Nov. 24. For Iraqis, the breakthrough was bittersweet because they won concessions from the Americans but must accept the presence of U.S. troops until 2012.

"It's the best possible, available option," said government spokesman Ali al-Dabbagh. He was referring to the conflict between Iraq's desire for full sovereignty and control over security and its need for American support and cooperation to achieve that goal.

Al-Dabbagh described the pact — intended to supplant the U.N. mandate expiring Dec. 31 — as an "agreement on the withdrawal of U.S. troops," and Washington welcomed the Cabinet's approval.

"While the process is not yet complete, we remain hopeful and confident we'll soon have an agreement that serves both the people of Iraq and the United States well and sends a signal to the region and the world that both our governments are committed to a stable, secure and democratic Iraq," said Gordon Johndroe, spokesman for the White House's National Security Council.

There is a good chance parliament will pass the agreement with a large majority, since the parties that make up Prime Minister Nouri al-Maliki's coalition government dominate the legislature.

The pact was due to be completed by the end of July, but negotiations stumbled over parts pertaining to Iraqi sovereignty and judicial oversight.

Al-Dabbagh said Iraq's government has received U.S. assurances that President-elect Barack Obama would honor the agreement, and pointed out that each side has the right to repeal it after giving one year's notice. Obama, who takes office in January, has said he would pull U.S. combat troops out of Iraq within 16 months of moving into the White House — or May 2010.

Iraq's neighbors and U.S. adversaries, Iran and Syria, oppose the pact, arguing that the immediate withdrawal of U.S. forces offered the best option for Iraq.

The Iraqi government sought to allay their fears, amending the document to prohibit the Americans from using Iraqi territory to attack neighboring nations.

The Cabinet's decision was made amid violence, despite a dramatic improvement in security over the past year. Fresh attacks underlined doubts about whether Iraq's nascent security forces can stand without U.S. military support and training.