Iraq's Shiite prime minister, struggling to prevent widespread 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 meeting with U.S. President George W. Bush next week.

On Saturday, a prominent Sunni religious leader warned Arab governments and the international community that Iraq's escalating sectarian violence will spread throughout the Mideast unless they withdraw their support for al-Maliki's Shiite-led 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.

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

Shiite politicians loyal to radical anti-American Shiite cleric Muqtada al-Sadr also 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.

Sadrist lawmaker Qusai Abdul-Wahab blamed U.S. forces for Thursday's deadly attack on Sadr City because they failed to provide security. Sunni insurgents killed 215 people in the Shiite slum with mortars and five car bombs in the deadliest attack of the war.

As U.S. Vice President Dick Cheney traveled to the neighboring Sunni country of Saudi Arabia on Saturday to seek King Abdullah's help in calming Iraq down, this country'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.

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. It also banned all commercial flights at the capital's international airport.

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 vehicular traffic for one more day.

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In Diyala province, a hotbed of Iraq's Sunni-Arab insurgency, gunmen raided two Shiite homes late Friday night, police said. The attack targeted members of the al-Sawed Shiite tribe in the village of Balad Ruz, 45 miles northeast of Baghdad, according to a police officer who spoke on condition of anonymity to protect his own security, as officials often do in the increasingly volatile province.

The gunmen broke into the both houses as their large extended families slept, marched everyone outside, lined up the 21 men and shot and killed them with light weapons as the women and children watched, said police.

Police could not reach the remote village to collect the bodies and take them to a morgue until Saturday morning, police said, adding that they don't known whether the attack was motivated by sectarian hatred or a tribal dispute.

In other areas of Diyala province, a largely rural area of farms and orchards, police killed 36 insurgents and wounded dozens of others in clashes in several locations Saturday, police said.

U.S. and Iraqi forces also conducted several raids north of Baghdad on Saturday, killing 22 insurgents and an Iraqi civilian, and destroying a factory being used to make roadside bombs, the military said.

In western Iraq, a U.S. Marine 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, 53 American service members have died this month in Iraq.

Scattered violence was reported in Baghdad on Saturday as rockets and mortar shells hit three mostly Shiite areas, killing one person and wounding 15, police said. Three of the injured were hit near a memorial service being held in Sadr City for victims of Thursday's deadly attack.

An official from al-Sadr's main office in the slum visited hospitals treating some of the 257 people who had been wounded, and he gave them small donations of cash in envelopes.

Baghdad was much quieter than it had been on Friday, when rampaging militiamen burned and blew up four mosques and torched several homes in the mostly Shiite neighborhood of Hurriyah, police said. Iraqi soldiers at a nearby army post failed to intervene in the assault by suspected members of the Shiite Mahdi Army militia or subsequent attacks that killed as many as 25 Sunnis, said police Capt. Jamil Hussein.

The U.S. military said Saturday that Iraqi soldiers securing the Hurriyah area had found only one mosque that had been burned and were unable to confirm media reports that six Sunni civilians had been dragged out of Friday prayers and burned to death with kerosene during the attacks there Friday.

The sharp divisions between Shiite and Sunni officials remained obvious Saturday.

On Friday, al Sadr, the anti-American Shiite cleric, urged al-Dhari, the Sunni leader, to issue a religious edict condemning Sunni attacks on Shiites.

In an apparent response, Al-Dhari said during his news conference in Cairo, Egypt, on Saturday that his Association of Muslim Scholars has repeatedly condemned the killing of Iraqi Muslims and attacks on their homes and mosques.

The Sunni leader, who lives in Jordan, also dismissed the arrest warrant issued against him.

Sunni groups, who have accused al-Maliki's government of not trying to disband Shiite militias, recently said the arrest warrant marked the end of the national reconciliation plan that al-Maliki presented in June.

Al-Dhari, an outspoken critic of the government and the U.S. occupation, alleged that the Shiite-led government was using the 24-hour curfew as a way to carry out attacks against Sunnis.

"The government and the occupation forces are preparing the suitable environments to the militias and killing gangs, by imposing the curfew ones or twice a week to attack our people (Sunnis)," al-Dhari said.

But he also urged Iraqis not to be lured into continuing the cycle of violence.

"Be patient and practice steadfastness and don't be lured into this sedition that aims to destroy" Iraq, he said.

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