Bowing to intense pressure, Prime Minister Ibrahim al-Jaafari agreed Thursday to allow Shiite lawmakers to find someone else to head the new government, abandoning his claim on another term in the face of Sunni and Kurdish opposition.

Iraqi President Jalal Talabani, left, Iraqi politician Hussain al-Shahristani, center, and US Ambassador to Iraq Zalmay Khalilzad sit during closed door meetings Thursday April 20, 2006 in Baghdad, Iraq. Iraqi political parties agreed to postpone their scheduled parliament session until Saturday as Prime Minister Ibrahim al-Jaafari cleared the way for Shiite leaders to withdraw his nomination for a second term Thursday, a step that could mark a breakthrough in the months-long effort to form a new government.[AP]

Al-Jaafari's abrupt reversal was an apparent breakthrough in the monthslong struggle to form a national unity government. The Bush administration hopes such a government will curb Iraq's slide toward anarchy and enable the U.S. to start bringing home its 133,000 troops.

Leaders in the seven-party Shiite alliance, the largest bloc in the 275-member parliament, were to meet Friday to begin choosing a replacement. But their field of candidates lacks stature and power, raising questions whether the new prime minister will be any more successful than al-Jaafari in confronting sectarian violence and the brutal insurgency.

It was unclear why al-Jaafari suddenly decided to relinquish the nomination that he won by a single vote with backing from radical anti-American cleric Muqtada al-Sadr during a ballot among Shiite lawmakers two months ago. Al-Jaafari had insisted Wednesday that stepping aside was "out of the question."

But in a letter Thursday to the executive committee of the United Iraqi Alliance, the Shiite coalition, al-Jaafari wrote that he was prepared to "make any sacrifice to achieve" the organization's goals. "I tell you, you chose me, and I return this choice to you to do as you see fit."

"I cannot allow myself to be an obstacle, or appear to be an obstacle," al-Jaafari said in an emotional address on national television. He said he agreed to a new vote so that his fellow Shiite lawmakers "can think with complete freedom and see what they wish to do."

However, Kurdish politician Mahmoud Othman said al-Jaafari's change of heart followed meetings Wednesday in the Shiite holy city of Najaf between U.N. envoy Ashraf Qazi and both al-Sadr and Grand Ayatollah Ali al-Sistani, the nation's most prestigious Shiite cleric.

"There was a signal from Najaf," Othman told The Associated Press. "Qazi's meetings with (al-Sistani) and al-Sadr were the chief reason that untied the knot."

Aides to al-Sistani, the spiritual leader of the Shiite alliance, said the ayatollah was frustrated over the deadlock in forming a government and alarmed over the rise in sectarian violence that followed the Feb. 22 bombing of a Shiite shrine in Samarra.

In Washington, State Department spokesman Sean McCormack said there were "indications" the impasse would be resolved. He called for a strong and effective government that could "begin to repay the trust put in the political parties and the political leaders by the Iraqi people."

Many Shiite politicians had been quietly pressing al-Jaafari to step down, but were reluctant to force him out for fear it would shatter the Shiite alliance and make the coalition appear weak.

Stepping up the pressure this month, Secretary of State Condoleezza Rice and British Foreign Secretary Jack Straw flew to Baghdad and demanded quick action to resolve the impasse. However, several Iraqi figures complained the U.S. and British intervention had prompted al-Jaafari's supporters to dig in their heels against what many Iraqis considered foreign interference.

Shiite alliance leaders were to meet Friday to decide how to choose a nominee. If representatives of the seven alliance parties cannot reach a consensus on a single candidate, they will put several choices to a vote before the bloc's 130 parliament members Saturday, officials said.

It was unclear whether al-Jaafari's supporters would insist on his being among any candidates put to a vote, since he did not explicitly say he was out of the running.

The final choice would be presented to parliament later Saturday.

As the largest bloc in parliament with 130 seats, the Shiite alliance gets to name the prime minister subject to parliament approval.

But the Shiites lack the votes to guarantee their candidate's approval unless they have the backing of the Sunnis and Kurds, whom they need as partners to govern.

Sunnis and Kurds blame al-Jaafari for the increasing sectarian tensions and for failing to consult his coalition partners. Kurds accused him of failing to keep commitments over oil-rich Kirkuk, which the Kurds want to incorporate into their three-province self-ruled region in the north.

With the issue over the premiership nearing resolution, Sunni and Kurdish politicians expressed optimism that the new government could be formed quickly.

"I am confident we will succeed in forming the national unity government that all Iraqis are hoping for," Sunni elder statesman Adnan Pachachi told reporters.

Bassem Sharif, a prominent Shiite lawmaker, said the alliance "is leaning toward" replacing al-Jaafari. "The majority opinion is in favor of this."

Names most often mentioned as possible replacements include two members of al-Jaafari's Dawa party, Ali al-Adeeb and Jawad al-Maliki. Neither is widely known among Iraqis, and neither has extensive experience in administration or government.

Al-Maliki, who fled Iraq in the 1980s and settled in Syria, is considered more of a Shiite hard-liner than al-Jaafari. Al-Adeeb lived for many years in Iran before returning to Iraq after the collapse of Saddam Hussein's regime in 2003.

Vice President Adil Abdul-Mahdi is among the most capable and experienced Shiite figures but is considered unlikely for the post because of opposition within the alliance to a nominee from the biggest party, the Supreme Council for the Islamic Revolution in Iraq, or SCIRI. Abdul-Mahdi lost to al-Jaafari in the February vote.

Despite the optimism, much could still go wrong. The parties must work out how to divvy up ministries ¡ª particularly the powerful defense, interior and oil portfolios.

Whoever gets the prime minister's job will face enormous problems, not only in coping with sectarian violence, the armed insurgency and a crumbling economy but also in maneuvering between SCIRI's powerful leader, Abdul-Aziz al-Hakim, and al-Sadr.

Al-Hakim and al-Sadr come from two of the most prestigious Shiite families, and each aspires to leadership of the majority Shiite community. Armed militias affiliated with the two men are engaged in an intense struggle for power in towns and cities throughout the Shiite heartland south of Baghdad.

Al-Hakim's party controls the Interior Ministry, whose commandos have been blamed by many Sunni Arabs for harboring death squads that target Sunni civilians. Al-Sadr's Mahdi militia was believed responsible for many of the attacks against Sunni mosques following the Samarra bombing.