BAGHDAD (Reuters) – U.S. and Iraqi negotiators have ended efforts to reach a formal security pact before President George W. Bush leaves office in favour of an interim deal, the Washington Post said on Sunday, citing senior U.S. officials.

The two sides had been negotiating a Status of Forces Agreement that would provide a legal basis for U.S. troops to remain when a U.N. mandate expires at the end of the year.

But in the past week Iraqi leaders have spoken of only agreeing what they call a memorandum of understanding. Shi’ite Prime Minister Nuri al-Maliki has also raised for the first time the idea of setting a timetable for U.S. troops to leave Iraq.

The Washington Post quoted one U.S. official close to the negotiations as saying “we are talking about dates,” even though Bush has previously rebuffed calls for a timetable.

Iraq is a major issue in November’s presidential election battle between Republican John McCain and Democrat Barack Obama. McCain supports the Bush administration’s current strategy, while Obama has called for a timetable for withdrawal.

Iraqi Vice President Tareq al-Hashemi, a Sunni Arab, added his support for a withdrawal timetable.

“Iraqis must know when the American and other forces will leave Iraqi land. It is our right to know, and know the truth of where the situation stands, if there is an intention for American forces to leave or not,” Hashemi told Iraqiya state television in an interview broadcast late on Saturday.

The Post said the “bridge” security document would be limited in both time and scope and would allow basic U.S. military operations to continue once the U.N. mandate ended.

Iraq has rejected a number of Washington’s demands, insisting they infringe on the country’s sovereignty.

The document now under discussion with Iraq was likely to cover only 2009, the Post said.

Negotiators expected it to include a “time horizon,” with specific goals for a U.S. troop withdrawal from Baghdad and other cities and installations, it added.

The fixed dates are likely to include caveats referring to the ability of Iraqi forces to take over security.

PRESSURE

There is strong domestic pressure in Iraq to set dates for a withdrawal of U.S. forces, especially with violence at a four-year low and with Iraqi security forces getting larger.

Maliki’s political opponents would also likely try to exploit the issue of an undefined U.S. troop presence in provincial elections later this year.

The most contentious unresolved issue was the legal immunity of U.S. troops in Iraq, the Post reported.

U.S. officials have said this is non-negotiable. But Iraq’s deputy parliament speaker has said lawmakers would probably veto any deal that gave U.S. soldiers immunity from Iraqi law.

The Bush administration has always opposed setting any withdrawal timetable, saying to do so would allow militant groups to lie low and wait until U.S. troops in Iraq have left.

U.S. troop levels are already being cut, with the last of five additional combat brigades Bush deployed last year expected to pull out this month. That will leave 15 combat brigades in Iraq, or around 140,000 soldiers.

Washington was considering withdrawing additional troops beginning in September, The New York Times reported on Sunday, citing administration and military officials.

The withdrawal stemmed partly from the need for more U.S. troops in Afghanistan to fight the rising insurgency by the Taliban and other fighters.

No final decisions had been made, but up to three combat brigades in Iraq could be withdrawn, or slated for withdrawal, by the end of the administration in January, the Times said.