A car bomb killed six people Saturday near a Shiite shrine south of Baghdad, and the death toll from the deadliest attack of the year rose to nearly 90. A senior official warned Iraq was in an "undeclared civil war" that can be curbed only by a strong government and greater powers for security services.

Iraqi mourners lay their heads on the coffin of a policeman who was killed in Friday's suicide attack on the Buratha mosque which killed 79 people and wounded more than 160 Saturday April 8, 2006 in Najaf, 160 km (100) miles south of Baghdad, Iraq. Relatives and friends of Shiite Muslims killed in a deadly mosque attack buried their dead Saturday, carrying coffins through the streets, chanting religious rites and beating their heads and chests. [AP]

With sectarian tensions rising, U.S. Marines on Saturday beat back the largest attack in weeks by Sunni Arab insurgents in the western city of Ramadi ¡ª another sign of the crisis facing this country three years after Baghdad fell to U.S. forces.

The car bomb exploded at a small shrine in the Euphrates River town of Musayyib, 40 miles south of Baghdad. Police said most of the six dead and 14 wounded were Shiite pilgrims visiting the shrine.

Fears of more attacks are running high in Shiite areas following the Thursday car bombing that killed 10 in the Shiite holy city of Najaf and the suicide attack the following day against a Shiite mosque in Baghdad ¡ª the deadliest attack in Iraq this year.

The attacks on houses of worship have stoked tensions between Shiite and Sunni Muslims, especially after the Feb. 22 bombing of a Shiite shrine in Samarra, an act that triggered reprisal attacks against Sunni mosques and clerics.

Despite the violence, U.S. officials have discounted talk of civil war. However, a senior Iraqi official said Saturday that an "undeclared civil war" had already been raging for more than a year.

"Is there a civil war? Yes, there is an undeclared civil war that has been there for a year or more," Maj. Gen. Hussein Kamal told The Associated Press. "All these bodies that are discovered in Baghdad, the slaughter of pilgrims heading to holy sites, the explosions, the destruction, the attacks against the mosques are all part of this."

His comments were echoed by Egyptian President Hosni Mubarak.

"Civil war has almost started among Shiites, Sunnis, Kurds and those who are coming from Asia. The situation is uneasy and I don't know how would Iraq be brought together," Mubarak said in an interview broadcast Saturday on Al-Arabiya satellite television.

Kamal said the country would still be spared from all-out sectarian war "if a strong government is formed, if the security forces are given wide powers and if they are able to defeat the terrorists."

"Then we might be able to overcome this crisis," he said.

The death toll from the Friday bombing of the Buratha mosque in north Baghdad rose to 85 because some of the wounded died, Dr. Riyadh Abdul Ameer of the Health Ministry said. Officials said the death toll could rise because of severe injuries among the 156 people wounded in the attack by suicide bombers, including one dressed as a woman.

Also Saturday, Sunni insurgents launched their strongest attack in six weeks against the Anbar provincial government headquarters in Ramadi, 75 miles west of Baghdad. There were no U.S. casualties, Marines said.

A U.S. Air Force F-18 fighter bombed insurgent positions, unleashing thunderous explosions that shook the city. U.S. Marines guarding the government headquarters fought back with anti-tank rockets, machine guns and small arms fire.

Sporadic shooting occurred around the government building after sunset, and an Iraqi soldier was killed Saturday in a separate fight in Ramadi, U.S. officials said. Three Iraqi soldiers were wounded in a clash with insurgents in Fallujah, about 30 miles east of Ramadi, police said.

The U.S. military reported Saturday that a U.S. Marine died from wounds suffered in hostile action the day before in Anbar province but gave no further details.

The New York Times reported in its online edition Saturday that an internal staff report by the U.S. Embassy and the military command rated overall stability of six of Iraq's 18 provinces "serious" and one "critical." The report was dated Jan. 31, the Times said.

The newspaper said provinces where overall stability was rated "serious" included Baghdad and oil-rich Basra, where Shiite militias wield considerable influence. Anbar province, which includes Ramadi and Fallujah, was rated "critical," the newspaper said.

"This report should be seen in the broader context of development in Iraq as it relates to the economy, governance and security," Dan Speckhard, the U.S. reconstruction chief for Iraq, said in a statement.

He said significant progress was being made in economic development and local governance after "decades of mismanagement" by Saddam Hussein's regime.

Efforts to form a strong, broadbased government including Sunnis, Shiites and Kurds have stalled over Sunni and Kurdish opposition to Prime Minister Ibrahim al-Jaafari, the Shiite candidate to lead the next administration. Opponents accuse al-Jaafari of failing to stem sectarian violence.

However, al-Jaafari has refused to step aside, and his Shiite coalition has been reluctant to reconsider his nomination for fear of splintering their ranks. Shiite officials were to meet, possibly as soon as Sunday, to discuss the stalemate at the urging of the country's top Shiite leader, Grand Ayatollah Ali al-Sistani.

Al-Jaafari's allies suggested the meeting would be to affirm the prime minister's nomination, which he won by a single vote during balloting last February among Shiite lawmakers who won seats in parliament in the December elections.

"So far, we still have one candidate ... and that is Dr. Ibrahim al-Jaafari," Jawad al-Maliki, a key member of the prime minister's Dawa party. said. "If there is an opinion to be discussed within the alliance, then it must be discussed through ... democratic means."

Al-Maliki said he understood that al-Sistani wanted the alliance to resolve the crisis "but I did not hear a call" for al-Jaafari to step down. But he added that "anything is possible."

Khalid al-Attiyah, an independent member of the Shiite alliance, said several options were under discussion, including replacing al-Jaafari with Vice President Adil Abdul-Mahdi, who lost the February vote.

But al-Attiyah said al-Jaafari's party would oppose that. Abdul-Mahdi is a member of the largest Shiite party, the Supreme Council for the Islamic Revolution in Iraq.

Other proposals include naming another candidate from Dawa or someone not affiliated with either of the two big Shiite parties, al-Attiyah said.

In other developments Saturday:

? Police found four headless bodies showing signs of torture that were dumped on a farm about 20 miles north of Baghdad.

? A mortar round hit a house near the Education Ministry in central Baghdad, killing two men, police said.

_Gunmen killed a Shiite cigarette vendor and police found the body of a man killed by a roadside bomb near a highway.