WASHINGTON - US Vice President Joe Biden on Tuesday called Iraqi prime minister and parliament speaker, urging them to work through their political differences together, White House said in a statement.

White House said Biden spoke with Iraqi Prime Minister Nuri al-Maliki and Iraqi parliament speaker Osama al-Nujaifi separately to discuss the "current political climate" in Baghdad.

Biden stressed the urgent need for Maliki and the leaders from other major political blocs to "meet and work through their differences together," said the White House.

Biden's call came at a time when Iraq is stuck in a deepening political crisis after the country's highest judiciary body issued an arrest warrant for Vice President Tariq al-Hashimi on terror charges on Monday.

Biden told the two Iraqi leaders that the United States is "monitoring events in Iraq closely."

"He emphasized the United States' commitment to a long-term strategic partnership with Iraq, our support for an inclusive partnership government and the importance of acting in a manner consistent with the rule of law and Iraq' s constitution," said the White House.

The latest political row came after Hashimi's Sunni-backed parliamentary bloc of Iraqia, headed by Ayad Allawi, boycotted the parliament sessions since Saturday in protest over Maliki's alleged attempts to monopolize power after the US troops pulled out of the country.

On Sunday, Maliki asked the parliament to withdraw confidence from his Sunni deputy Salih al-Mutlak after the latter described Maliki as "dictator."

The latest development shows the growing tensions between Prime Minister Nuri al-Maliki's leading Shiite bloc and his political rivals, as the US troops concluded their withdrawal plan on Sunday.