Baghdad ? A heated parliamentary debate on the U.S.-Iraq security treaty was called to an early close Wednesday as lawmakers loyal to anti-U.S. cleric Muqtada al-Sadr scuffled with security guards for the foreign minister and the speaker of the legislature and his two deputies.

The session was chaotic from the start, with lawmakers shouting at each other. Speaker Mahmoud al-Mashhadani added to the din by repeatedly yelling at legislators to sit down or keep quiet, but failed to restore order.

The turmoil followed the announcement by two small political factions that they would join al-Sadr’s supporters in opposing the security pact, which would allow American forces to stay in Iraq for three more years.

The deal is backed by the governing coalition, which holds a majority in parliament, but Prime Minister Nouri al-Maliki is campaigning for help from other blocs in hopes of passing the measure with broader support in a vote by legislators Monday.