Iraq closed its borders with Iran and Syria as US and Iraqi troops tightened their grip on Baghdad today, setting up more checkpoints that stopped and searched even official convoys for weapons.
An Interior Ministry official, who spoke on condition of anonymity, said the closure of Iraq's four border crossings with Iran and two with Syria took effect yesterday.
US officials have long accused Syria of allowing foreign fighters to cross its long, porous border into Iraq, and at the weekend presented evidence of what they said was Iranian-manufactured weapons being smuggled into Iraq.
"The plan to close the borders went into effect last night. Many points were closed, but I can't confirm that all were shut," US military spokesman Lieutenant-Colonel Christopher Garver said.
There was no immediate confirmation from Tehran or Damascus, both of which deny involvement in Iraq's chaos.
Iraq had said it would shut the borders for 72 hours. The US military said yesterday the aim was to choke off the flow of weapons and foreign fighters into the country.
The closures came as thousands of US and Iraqi troops stepped up an offensive in Baghdad, the epicentre of sectarian violence between minority Sunnis and majority Shias that has pitched the country toward all-out civil war.
Military analysts say many militiamen were likely to lie low or leave Baghdad until the operation is completed rather than seek confrontation with US and Iraqi forces.
Fewer members of the Mehdi Army militia of radical cleric Moqtada al-Sadr have been seen on the streets of their stronghold, the sprawling Sadr City slum in east Baghdad, in the past week.
Several Mehdi Army commanders are also reported to have left the capital to avoid arrest.
The United States has identified the militia as the greatest threat to peace in Iraq and hundreds of Mehdi Army members have been arrested.
The US military and Iraqi government officials have said Sadr himself left Iraq for Iran ahead of the crackdown, but an official of Sadr's political movment, Salam al-Maliki, said he was still in Iraq.