FACTBOX - Iraq's thorny security negotiations with U.S.

(Reuters) - Iraqi Prime Minister Nuri al-Maliki on Monday raised the prospect of setting a timetable for the withdrawal of U.S. troops as part of negotiations over a new security deal. Following are key facts about the talks:

WHAT IS BEING NEGOTIATED?

The United States is negotiating a Status of Forces Agreement (SOFA) that would provide a legal basis for U.S. troops to stay in Iraq after December 31, when their U.N. mandate expires. Washington has set a goal of completing talks by the end of July, although Iraqi officials say that might be optimistic. Maliki said a memorandum of understanding could cover terms of the security deal including a possible withdrawal timetable. Such a memorandum may function as an interim deal until a formal SOFA is agreed.

WHAT HAVE BEEN THE POINTS OF CONTENTION?

Any withdrawal timetable will likely cause consternation in Washington. The Bush administration argues a timetable would give militants an advantage.

Iraq said last week Washington was showing flexibility on some issues, which officials said included dropping a demand for immunity from prosecution for private contractors working for the U.S. government. Control of military operations and airspace are other points of contention, along with the detention of Iraqi prisoners. Officials say planned U.S. military operations will be vetted by joint committees.

Washington has SOFA pacts with many countries, and they typically exempt U.S. troops from facing trial or prison abroad. Washington is highly unlikely to back down on this.

The United States and Iraqi governments have each said they do not want permanent U.S. bases in Iraq.

WHO IS CRITICISING THE TALKS?