BAGHDAD (Reuters) -Egyptian President Hosni Mubarak has warned that civil war had started in Iraq, where three consecutive days of bombings killed about 100 people, inflaming sectarian tensions.

The caution comes as Shi’ite leaders are to meet on Sunday in another attempt to break an impasse over the prime minister, hoping to pave the way for a unity government many see as the only way to avert open civil war.

“It’s not on the threshold (of civil war). It’s pretty much started. There are Sunnis, Shi’ites, Kurds and those types which come from Asia,” Mubarak said in an interview aired on Saturday on pan-Arab satellite television channel Al Arabiya.

Mubarak said that the large Shi’ite Muslim presence in Arab states were more loyal to Iran than their own countries, echoing accusations made by his fellow Sunnis in Iraq about their country’s Shi’ite leaders.

Hours earlier, a car bomb killed at least six Shi’ite pilgrims and wounded 16 in the town of Musayib south of Baghdad, police said, the latest in a wave of attacks that raised fresh fears of full-blown communal conflict.

Enraged town residents at the scene of the blast threw stones at U.S. troops in Humvees who fired warning shots in the air. One man also blamed fractious Iraqi leaders, who are struggling to form a government four months after elections.

“This is because of the Americans. It is their doing while (our) politicians just sit in their seats of power. Is this what they call a democracy?,” he yelled as people picked up thick pieces of shrapnel.

Powerful Shi’ite leader Abdul Aziz al-Hakim had urged his followers to stand firm against what he called an al Qaeda campaign to ignite sectarian civil war with bombings like one on Friday that killed at least 70 people.

That triple suicide bombing at the Buratha mosque in Baghdad, the biggest single suicide attack on a Shi’ite target since November 2005, raised fresh fears of a full-blown communal conflict, with the United States, Britain and the United Nations quickly urging Iraqi unity.

Hakim’s speech, delivered on the anniversary of the execution of top Shi’ite cleric Muhammad Baqir al-Sadr and his sister by Saddam Hussein, called for unity between Iraq’s main Shi’ite, Kurdish and Arab Sunni communities.

But he also reminded majority Shi’ites of their decades of suffering under Saddam’s Sunni-dominated regime and urged them to resist attempts by the al Qaeda leader in Iraq, Abu Musab al Zarqawi, to plunge the country into open civil war.

“(Sunni) militants and insurgents want to return Iraq to Saddam’s formula,” said Hakim, leader of the pro-Iranian Supreme Council for the Islamic Revolution in Iraq (SCIRI), a party in the ruling Shi’ite Alliance.

“This nation will not fall into the trap of sectarian war that is being pursued by Zarqawi’s groups.”

Sectarian tensions have been rising since the bombing of a Shi’ite shrine on February 22 touched off reprisals and pushed Iraq to the brink of civil war.

The latest bombs provided more proof that Iraqi leaders, deadlocked over a government, are unable to tackle the bloodshed which is consuming the country.

The United States and Britain have been stepping up pressure on Iraqi leaders to form a government in the hope that the political process could undermine a Sunni insurgency and ease sectarian violence.

Hakim’s Alliance is under intense pressure to replace Ibrahim al-Jaafari as its nominee for prime minister to break the deadlock over postwar Iraq’s first full-term government.

But Jaafari, who is the serving prime minister, refuses to step aside despite calls, even from within his own Alliance, and from Sunni and Kurdish leaders who say he has failed in office.

Mubarak said of the Arab countries around Iraq: “There are Shi’ites in all of those states in very big percentages, and the loyalty of those Shi’ites is to Iran, most of them are loyal to Iran. Their loyalty is not to their particular countries.”

The Egyptian leader warned against an immediate U.S. troop withdrawal.

“Now? It would be a disaster … It would become an arena for a brutal civil war and then terrorist operations would flare up not just in Iraq, but in very many places.”