Radical Shi'ite cleric Moqtada al-Sadr has ordered heads of his Mehdi Army militia to leave Iraq and asked the government to arrest "outlaws" under a US-backed crackdown, Iraq's President said yesterday.

President Jalal Talabani made the remarks after Iraq closed its borders with Iran and Syria and as US and Iraqi troops tightened their grip on Baghdad, searching neighbourhoods and setting up checkpoints that searched even official convoys. Mr Talabani said he was unaware of Sadr's whereabouts. The US military has said he is in Iran, but his aides insist he is in Iraq's holy Shi'ite city Najaf. An Iraqi government official said he was in Tehran, but only for a short visit.

"I think many of his top Mehdi Army officials have been ordered to leave Iraq to make the mission of the security forces easier," the President was quoted as saying in a statement from his office. It added Sadr supported the crackdown and had given the government the go-ahead to arrest any "outlaws".

Mr Talabani told a news conference that Sadr had asked Mehdi members to leave the country.

There have been reports that several commanders of the Mehdi Army, which Washington calls the greatest threat to Iraq's security, have fled the capital. US and Iraqi forces have arrested hundreds of Mehdi Army members in recent months.

Residents of Sadr City, stronghold of the Mehdi Army, reported seeing fewer militiamen on the streets as Operation Imposing Law, a new crackdown to pacify the lawless capital, gathers pace.

Insurgents defied a sweep by US and Iraqi troops of the capital's volatile southern, mainly Sunni, Doura district, exploding two car bombs that killed four people. A bomb planted on a bus in Sadr City killed three people.

Some 3,000 Iraqi and British troops locked down the southern oil port of Basra, where feuding Shi'ite groups and criminal gangs have threatened security. Checkpoints were tightened on all roads out of the city as part of a 72-hour crackdown. 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 on Wednesday.

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.