BAGHDAD, Iraq (AP) – Pressure mounted yesterday on Prime Minister Ibrahim al-Jaafari to step aside as the Shiite bloc’s nominee for a second term, with some fellow Shiites urging him to withdraw to break the deadlock over a new government.

US officials believe formation of a government of national unity would be a major step towards calming the insurgency and restoring order three years after the US-led invasion toppled Saddam Hussein. That would enable the US and its coalition partners to begin withdrawing troops.

But talks among Iraqi political leaders have bogged down, prompting Sunni Arab and Kurdish politicians to call for al-Jaafari’s replacement as the nominee of the Shiite bloc. The Shiites get first crack at the prime minister’s job because they are the largest bloc in parliament.

Al-Jaafari, a physician who spent years in exile in Iran and Britain, edged out Vice President Adil Abdul-Mahdi for the nomination during an alliance caucus in February, thanks to the support of radical Shiite cleric Muqtada al-Sadr.

The prospect of a prime minister politically beholden to the vehemently anti-American al-Sadr has alarmed both Iraqi and U.S. officials. On yesterday, al-Sadr’s bloc in parliament reaffirmed its support for al-Jaafari.

“We will not abandon our decision regarding al-Jaafari’s candidacy,” the bloc’s leader in parliament, Salam al-Maliki, told Al-Arabiya television.

Shiite officials said that despite opposition to al-Jaafari, Shiite leaders were hesitant to move against him for fear of splitting the alliance.

US officials have grown increasingly impatient with the pace of government talks which began after the Dec. 15 elections. In a statement released Saturday, U.S. Ambassador Zalmay Khalilzad urged the Iraqis to speed up the process to prevent the country from sliding into civil war.