Secretary of State Condoleezza Rice and British Foreign Secretary Jack Straw arrived in Baghdad on Sunday, U.S. and British officials said. The surprise visits come amid growing pressure on Prime Minister Ibrahim al-Jaafari to step aside as the Shiite nominee for a second term to break the stalemate in talks on forming a new government. The British official, who spoke on condition of anonymity under embassy rules, refused to discuss the purpose of the visit but said Straw would meet with government officials to discuss progress on forming a new government. A U.S. Embassy spokesperson confirmed the visit but provided no other details. Talks among Shiite, Sunni and Kurdish leaders have stalled, in part because of opposition to al-Jaafari's nomination by the Shiite bloc. On Saturday, Shiite politician Qassim Dawoud joined Sunnis and Kurds in calling for a new Shiite nominee, the first time a Shiite figure has issued such a public call. Rice was last in Iraq in November, and Straw paid a visit in January. Rice and Straw, who had been in northern England, arrived during a driving rain and thunderstorm at a time when U.S. officials here have been expressing increasing impatience with the slow pace of government talks following the Dec. 15 elections. U.S. Ambassador Zalmay Khalilzad has urged the Iraqis to speed up the process to prevent the country from sliding into civil war. "The terrorists are seeking to provoke sectarian war, and Iraq needs a government of national unity in the face of this threat," Khalilzad said in a statement released Saturday. "This government needs to have a good program to govern from the center, and needs good ministers who are competent. Iraq is bleeding while they are moving at a very slow pace," he added. U.S. officials believe the formation of a government of national unity would be a major step toward calming the insurgency and restoring order three years after the U.S.-led invasion toppled Saddam Hussein. That would enable the U.S. 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. The Shiites get first crack at the prime minister's job because they are the largest bloc in parliament. Dawoud, a former Cabinet minister, said Saturday that four major parties within the Shiite alliance had agreed to "reconsider" al-Jaafari's nomination. But Jawad al-Maliki, a member of the prime minister's Dawa party, insisted to Al-Arabiya television that the alliance "is united in its position" and "is backing its candidate," meaning al-Jaafari. Other Shiite officials, speaking on condition of anonymity because of the sensitivity of the issue, said Dawoud was not alone in his opposition to al-Jaafari, and that representatives of major factions within the Shiite alliance would decide soon whether to withdraw the nomination. 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. 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 on Saturday.