Filed at 3:44 p.m. ET
BAGHDAD (Reuters) - 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 U.S.- backed crackdown, Iraq's president said on Thursday.
President Jalal Talabani made the remarks after Iraq closed its borders with Iran and Syria and as U.S. and Iraqi troops tightened their grip on Baghdad, patrolling neighborhoods and setting up checkpoints that searched even official convoys.
Insurgents defied a sweep by U.S. and Iraqi soldiers of the volatile southern, mainly Sunni, Doura district, exploding two car bombs that killed four people. A bomb planted on a bus in the Mehdi Army stronghold of Sadr City killed three people.
Talabani said he was unaware of Sadr's whereabouts. The U.S. military has said the anti-American cleric 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.
Washington calls the Mehdi militia the greatest threat to Iraq's security. U.S. and Iraqi forces have arrested hundreds of Mehdi Army members in recent months.
The statement from Talabani's office added that Sadr supported the crackdown and had given the government the go- ahead to arrest any ``outlaws.''
Talabani told a news conference that Sadr had asked Mehdi members to leave the country.
His comments and the melting away of many ordinary Mehdi fighters from Sadr City's streets are the clearest signs yet that the militia will not stand and fight like it did in 2004, when it twice rose up against American forces.
Some Shi'ite officials outside Sadr's movement say the militia wants to avoid a battle to protect the young cleric's political gains. Sadr's movement holds a quarter of the parliamentary seats in the ruling Shi'ite Alliance of
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.
U.S. 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 were Iranian- manufactured weapons being smuggled into Iraq.
Iraq had said it would shut the borders for 72 hours. The U.S. military said on Wednesday border checkpoints were to be revamped to establish ``transfer points'' to search vehicles.
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.
TIPPED OFF
In Baghdad, low-flying fighter jets thundered over the capital, rattling windows. A spokesman for the U.S. military, Major Steven Lamb, said 17 suspects were arrested and three weapons caches seized.
The crackdown aims to clear Baghdad neighborhoods of militants and weapons and then secure them in a bid to break the power of Shi'ite militias and Sunni insurgents who have turned the capital's streets into killing fields.
But military analysts say the advance publicity given to the Baghdad security plan means many militiamen are likely to have left Baghdad or are lying low until the operation is completed, rather than confront security forces.
A senior Sadr official, Salam al-Maliki, told Reuters that although Sadrists backed the new security clampdown, ``some of the brothers who are wanted by the Americans have moved house because we've been targeted before.''
More checkpoints appeared overnight and residents reported that even official government or security convoys were stopped and asked for weapons permits and identification papers.
``I'd rather suffer from traffic jams than explosions. I am really happy they have finally decided to check all vehicles, including government convoys,'' said Hussein Alwan, the 21-year-old owner of a computer software shop.
Guns were seized even from civilians with permits for the weapons, and only people with Interior and Defense Ministry badges allowed to keep their arms. Some people were arrested for not having identification documents.