Baghdad ? Iraq’s Shiite prime minister, struggling to prevent sectarian violence from sending Iraq into full-fledged civil war, is facing strong criticism from top Shiite and Sunni Arab leaders alike as he prepares for a summit with President Bush next week.

On Saturday, a prominent Sunni religious leader warned that Iraq’s escalating sectarian violence will spread throughout the Middle East unless the international community withdraws support for Prime Minister Nouri al-Maliki’s government.

“I call on the Arab states, the Arab League and the United Nations to stop this government and withdraw its support from it. Otherwise, the disaster will occur and the turmoil will happen in Iraq and other countries,” said Sheik Harith al-Dhari, who heads the Association of Muslim Scholars.

Last week, Iraq’s Interior Ministry issued an arrest warrant against al-Dhari, saying he was wanted for inciting violence and terrorism.

On the other side of Iraq’s sectarian divide, Shiite politicians loyal to the radical anti-American Shiite cleric Muqtada al-Sadr have threatened to boycott parliament and the Cabinet if al-Maliki goes ahead with the planned summit in Jordan on Wednesday and Thursday. The political bloc, known as Sadrists, is a mainstay of support for al-Maliki.

The White House has said the meeting is still on.

Iran, the top U.S. rival in the region, had planned its own summit Saturday, inviting the presidents of Iraq and Syria in what was seen as a bid to assert its role as a powerbroker in Iraq. Syria did not respond, perhaps to avoid annoying the U.S., and Iraq’s president said he could not get to Iran before Sunday at the earliest because Baghdad’s airport was closed to commercial flights following a deadly attack Thursday in Sadr City.

Widespread violence

Suspected Sunni insurgents killed 215 people in the Shiite slum with mortars and five car bombs in the deadliest single attack of the war. On Saturday, Sadrist lawmaker Qusai Abdul-Wahab blamed U.S. forces for the attack, saying they failed to provide security.

As Vice President Dick Cheney traveled to the neighboring Sunni country of Saudi Arabia on Saturday to seek help in calming Iraq, Iraq’s sectarian violence shifted to Diyala province north of Baghdad, where gunmen broke into two Shiite homes and killed 21 men in front of their relatives, police said. U.S. and Iraqi forces also killed 58 insurgents during fighting in the same region.

In central Iraq, a suicide car bomber attacked a checkpoint near Fallujah, killing three Iraqi civilians and a U.S. service member, and wounding nine civilians and an American service member, the coalition said. The dead included two Iraqi children and an adult.

A U.S. Marine also died from wounds sustained while fighting in Anbar province on Friday, the military said, raising to at least 2,873 the number of U.S. servicemen who have died since the war began in 2003. So far, 54 American service members have died this month in Iraq.

Six people were killed in other violence in Iraq on Saturday, and 19 bodies were found, police said.

Iraq’s government has been unable to prevent revenge attacks by Shiite militias and Sunni Arab insurgents, despite the 24-hour curfew it imposed Thursday night on Baghdad’s 6 million residents. After only scattered violence occurred in Baghdad on Saturday, the government announced it would allow residents to leave their homes Sunday but keep the ban on all vehicles for another day.

Meanwhile, The New York Times reported Sunday that Iraqi militant groups have raised between $70 million and $200 million a year from various illegal activities to fund the insurgency. The newspaper, which cites a classified U.S. government report obtained by the Times, said the money has come from oil smuggling, kidnapping, counterfeiting and other activities.

The report said terrorist and insurgent groups in Iraq may also have extra money with which to finance terrorist organizations outside Iraq.