Updated

Pressure mounted Sunday on Prime Minister Ibrahim al-Jaafari to give up his bid for a new term amid anger over a recent surge of sectarian killing that has complicated already snarled negotiations on a new Iraqi government.

The delay in forming a government has prevented the parliament elected Dec. 15 from meeting since the vote was certified last month. But Kurdish and some Shiite officials said Sunday it should be ready to convene by the end of the week.

The political turmoil has left a dangerous leadership vacuum as Iraqi armed forces, backed by the U.S. military, battle to contain the violence that pushed Iraq to the brink of civil war following last month's bombing of a sacred Shiite shrine in Samarra and reprisal attacks against Sunnis.

Gunmen stormed a Sunni mosque early Sunday in west Baghdad, killing three people and wounding seven in a 25 minute gunbattle. Witnesses said U.S. helicopters hovered above the exchange of fire and American forces later moved in to stop the fighting and remove casualties.

Two relatives of an influential Sunni leader also were killed in a drive-by shooting in another part of west Baghdad.

Sunni Arab leaders blamed Shiite militiamen operating within Interior Ministry ranks for both attacks, but the ministry denied involvement.

Despite the violence, Gen. Peter Pace, the chairman of the Joint Chiefs of Staff, Iraq is not on the verge of civil war, though he acknowledged the situation was unstable.

"Anything can happen, I agree," Pace said on a news show, adding "I believe the Iraqi people have shown in the last week to 10 days that they do not want civil war."

Sunni and Shiite clerics, meanwhile, issued a joint appeal for Muslim unity and the protection of religious sites.

"Extinguish the flames of the sectarian treachery," said the followers of radical Shiite cleric Muqtada al-Sadr and members of the Sunni Endowment, a government agency responsible for Sunni mosques and shrines. "Every drop of blood shed is a waste."

U.S. officials believe a unity government that includes Iraq's main ethnic and religious communities is essential for stabilizing the country and allowing U.S. and other foreign forces to start pulling out in the summer.

Gen. John Abizaid, the chief of the U.S. Central Command, met with Iraqi leaders Saturday and urged them to resolved issues stalling the formation of a government.

"The shrine bombing exposed a lot of sectarian fissures that have been apparent for a while, but it was the first time I've seen it move in a direction that was unhelpful to the political process," Abizaid said.

"It shows that we need a government of national unity to emerge in Iraq. Too many delays in the formation of a national unity government will negatively affect the security situation," he added.

As the largest bloc in parliament, the Shiite United Iraqi Alliance gets the first chance to form a government, but it does not have sufficient seats to do so alone. Sunni, Kurdish and some secular parties are pressing the bloc to withdraw its nomination of al-Jaafari, who has served as prime minister in the transitional government that took power in April.

The Sunni Arab minority blames al-Jaafari for failing to control Shiite militiamen who attacked Sunni mosques and clerics after the Feb. 22 bombing of the Askariya mosque in Samarra. More than 500 people were killed in the violence, according to police and hospital accounts.

Khalaf al-Olayan, a leader of the main Sunni bloc in parliament, said Iraq has gone from "bad to worse."

"Al-Jaafari's government failed to solve the chaos that followed the Samarra explosions and did not take any measures to solve the security crisis that could have pushed the country into civil war," he said in comments posted on the Sunni Iraqi Accordance Front Web site.

Kurds are angry because they believe al-Jaafari is holding up resolution of their claims to control of the oil-rich city of Kirkuk.

"If al-Jaafari tries to form a government, he will not get any kind of cooperation," said Mahmoud Othman, a leading figure in the Kurdish bloc.

The Shiite alliance itself is divided: al-Jaafari won the nomination by a single vote at a Feb. 12 Shiite caucus. Some members are troubled by al-Jaafari's ties to al-Sadr, whose support was key in defeating Vice President Adil Abdul-Mahdi, the choice of powerful Shiite leader Abdul-Aziz al-Hakim.

Two lawmakers from al-Jaafari's Dawa Party visited the Shiite holy city of Najaf Saturday to seek the endorsement of Shiite spiritual leader, Grand Ayatollah Ali al-Sistani. They hinted al-Sistani approved of their candidate. But a senior al-Sistani aide, speaking on condition of anonymity because of the sensitivity of the dispute, said the cleric had indirectly suggested al-Jaafari should step aside.

On Sunday, it was the turn of Kurdish leaders to meet al-Sistani, with a delegation that also met with al-Sadr and other top religious leaders.

Othman said he expected a presidential decree to be issued Sunday summoning parliament to meet Thursday or Saturday. Haitham al-Husseini, an al-Hakim spokesman, agreed lawmakers would likely convene in the next few days.

But a member of the Dawa Party-Iraq Organization, which is close to al-Jaafari's party, rejected the idea of meeting until agreement is reached on a prime minister and president.

As the political wrangling continued, so did the violence.

Sheik Shaker Mahmoud, the imam at west Baghdad's al-Nour mosque, said the building was attacked by "a gang" driving Interior Ministry cars and wearing military uniforms. Masked gunmen guarded the bullet-scarred mosque Sunday, and at least two unexploded grenades could be seen.

The influential Sunni clerical Association of Muslim Scholars also blamed the Interior Ministry for the killing of a nephew and cousin of its leader, Harith al-Dhari. Their bodies were found in a bullet-riddled vehicle in west Baghdad, police said. An imam from a Sunni mosque south of the capital was wounded in the attack, the endowment said.

"These are false accusations. The ministry and the minister are not running death squads in the country," ministry official Maj. Falah al-Mohammedawi said.

Two policemen, a taxi driver and two electricity workers were killed in scattered gunfire in Baghdad and south of the capital. Police also found two shot-up bodies with hands and legs bound in a Shiite suburb in Baghdad.