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 under way "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.
Amid the political crisis, Allawi told US media earlier this month that Iraq was enduring the "most dangerous phase" of its modern history, with tensions soaring and the fledgling democracy in jeopardy.
Allawi also told CNN that the United States was morally obligated to use its diplomatic muscle to restore "sanity" to Iraq's political landscape.
"Sectarianism is coming back in force in this country," he warned.
Iraq has been rocked by waves of attacks in the month since US troops pulled out from the country they invaded eight years ago, and concern has soared about Iraqi forces' capabilities to maintain internal security.
"It's neither stable nor democratic, frankly speaking," Allawi said. "The terrorists are hitting again very severely, and Al-Qaeda is fully operational now in Iraq," he stresed, adding he did not want a return of US troops to Iraqi soil.
Washington, he argued, should use diplomacy to try to "bring about sanity to the political process and inclusivity."