The United States and Iraq have agreed to a draft security pact that requires U.S. troops to leave Iraq by the end of 2011 unless asked to stay, the Iraqi government said on Wednesday, although its implementation is far from certain.

Government spokesman Ali al-Dabbagh also said Baghdad will seek an extension of a UN mandate for the U.S. troops in Iraq – due to expire on Dec. 31 – if the pact is not in place by the end of this year.

The draft agreement also lets Iraq try U.S. troops for felonies committed off-duty. The concession on the legal immunity for U.S. forces represents the biggest bone of contention, Bush administration officials who asked not to be named told the Associated Press.

The draft, reached after months of halting and often tense talks, contains elements that are expected to further aggravate an already difficult effort to get the Iraqi government and parliament on board, the officials said.

The pact, hammered out over months of negotiations between Washington and Baghdad, has been submitted to Iraqi politicians for approval.

Iraqi Prime Minister Nouri al-Maliki was due to show the draft on Wednesday to the National Security Council, a consultative body that includes himself, President Jalal Talabani, the two vice-presidents, leaders of political blocs and the parliament speaker.

If they agree, he would submit the draft to his cabinet for their approval by two-thirds majority. The final step will be parliament's approval.

Top al-Qaeda leader killed in northern raid: military

In what appears to be another breakthrough for the Unites States in Iraq, the military said in a statement released Wednesday that the No. 2 leader of al-Qaeda in Iraq was killed during a raid in the northern city of Mosul.

The military statement described the man, a Moroccan known as Abu Qaswarah, as a charismatic leader who had trained in Afghanistan and managed to rally al-Qaeda followers in Iraq despite U.S. and Iraqi security gains.

U.S. troops killed Abu Qaswarah, also known as Abu Sara, on Oct. 5 after coming under fire during a raid on a building that served as an al-Qaeda "key command and control location," the military said.

Abu Qaswarah, one of five insurgents killed, was later positively identified, the military said, without elaborating.

The insurgent leader became the senior al-Qaeda emir of northern Iraq in June 2007 and had "historic ties to [the founder of al-Qaeda in Iraq] Abu Musab al-Zarqawi, and senior al-Qaeda leaders in Afghanistan and Pakistan," the military said.

It called him "al-Qaeda in Iraq's second-in-command" as the senior operational leader for al-Zarqawi's successor, Abu Ayyub al-Masri, also known as Abu Hamza al-Muhajir.

Abu Qaswarah directed the smuggling of foreign terrorists into northern Iraq, said Rear Adm. Patrick Driscoll, a U.S. spokesman in Baghdad.

He reportedly killed those who tried to return to their homelands rather than carry out suicide bombings and other attacks against Iraqis, he said.

The announcement would indicate that al-Qaeda in Iraq's leadership has maintained a presence despite recent reports that many had fled to Afghanistan and Pakistan, where fighting has been on the rise.

The death will cause a major disruption to the terror network, particularly in northern Iraq, the military said Wednesday.

Nationwide violence has declined drastically over the past year, particularly in Baghdad, but the U.S. military has consistently warned al-Qaeda and other insurgents remain a serious threat.

With files from Reuters