BAGHDAD, (Reuters) – Approval of a measure that would allow troops from Britain, Australia and some other nations to stay in Iraq after a U.N. mandate expires at year’s end fell hostage on Monday to a political row in Iraq’s parliament.

Parliament speaker Mahmoud al-Mashhadani suspended the body’s regular session until Jan. 7 after deputies demanded he stand down, said an official in the office of Khalid al-Attiya, the deputy speaker.

At the same time, 54 lawmakers called for a special session that could determine whether Mashhadani, a former doctor and Sunni politician who some lawmakers say insulted them in a recent session, is replaced, said Abdel Muhsin al-Sadoun, a Kurdish lawmaker.

By evening, discussions between political leaders were unable to break the impasse over Mashhadani. Hashim al-Taie, a Sunni Arab deputy, said parliament would reconvene on Tuesday.

The fracas raised doubts over whether Iraq would be able to approve in time a measure allowing Britain to keep its 4,100 troops in Iraq until the end of July, and also covering troops in Iraq from Australia, Estonia, El Salvador, Romania and NATO.

The presence of those troops is authorised by a U.N. mandate which expires at the end of December.

On Saturday, lawmakers rejected a draft law that would have permitted their continued presence, arguing that foreign relations required not legislation but treaties or agreements with individual countries.

Lawmakers had been saying that because time was short, the body was likely to issue an interim resolution, a memo or even a law allowing the forces to remain in Iraq until proper treaties or agreements were signed.

Under the draft law defeated last week, the foreign forces would have to cease combat operations at the end of May and withdraw completely by the end of July, more than six years after the U.S.-led invasion to topple Saddam Hussein.

Deputies did not appear to be opposed to the terms or the timetable established in the law, only to the format in which the withdrawal deal was framed. They said they wanted a format similar to that in a U.S.-Iraq bilateral security pact that allows 140,000 or so U.S. troops in Iraq to stay for three more years.

As violence subsides, the deal highlights Iraq’s growing control over its own security and a drawdown of foreign troops.

The ethnic slaughter and insurgent violence unleashed by the invasion have dropped significantly over recent months although suicide and car bombs remain common.

From next year, Iraqi police and soldiers will take the lead in ensuring security. U.S. combat forces will have to leave Iraqi cities and villages by the end of June and will not be able to conduct operations without Iraqi permission.