Biden urges Iraqi leaders to resolve political differences US Vice President Joe Biden urged Iraqi leaders to resolve their differences ahead of a possible national conference involving the nation's political parties, the White House said on Saturday. Biden called Iyad Allawi, leader of the Iraqiya political block, on Friday and Iraqi parliament speaker Osama al-Nujaifi on Saturday, and discussed "the importance of resolving outstanding issues through the political process." The two Iraqi leaders meanwhile described to Biden the deliberations underway "among all Iraqi political factions and parties in the run-up to a proposed national conference led by President Jalal Talabani," according to the White House statement. A political row has been festering in Iraq since shortly after US forces completed their withdrawal from Iraq in December and has pitted the Shiite-led government against the main Sunni-backed bloc, stoking sectarian tensions. The United Nations has joined the United States in urging calm but their calls for talks involving all of Iraq's political leaders have so far gone unheeded. Last month, the Iraqiya bloc began a boycott of parliament and cabinet to protest what it charged was Prime Minister Nuri al-Maliki's centralization of power, and has since called for Maliki to respect a power-sharing deal or quit. Authorities have issued an arrest warrant for Vice President Tareq al-Hashemi, a Sunni. Meanwhile Maliki, a Shiite, has said his Sunni deputy Saleh al-Mutlak should be sacked after the latter said the premier was "worse than Saddam Hussein." The Sunni-backed Iraqiya, which holds 82 seats in the 325-member parliament, has so far held back from pulling out its nine ministers from the national unity government. It won the most seats in March 2010 elections but was out-maneuvered by Maliki's alliance, which eventually formed the government after a prolonged impasse was finally broken in November of that year.