US Vice President Joe Biden Tuesday urged Iraqi Prime Minister Nuri al-Maliki to work with other parties to resolve a worsening crisis threatening Iraq's fragile political truce.
The nation's Sunni Arab Vice President Tareq al-Hashemi has defiantly denied terror charges lodged against him the day after US troops left Iraq -- bringing to an end the nine-year war.
A warrant has also been issued for Hashemi's arrest, spurring his Iraqiya bloc to say it would boycott cabinet meetings -- a move which comes as the unity government is to mark its first anniversary.
Biden spoke by phone with Maliki and with Iraqi Council of Representatives Speaker Osama al-Nujaifi "to discuss the current political climate in Baghdad," the White House said in a statement.
"The vice president told both leaders that the United States is monitoring events in Iraq closely," the statement added.
Biden also "stressed the urgent need for the prime minister and the leaders of the other major blocs to meet and work through their differences together."
At least 13 of the vice president's bodyguards have been detained in recent weeks, although it was unclear how many remain in custody.
Hashemi's office said only three were arrested, and has complained of "intentional harassment" in the form of a blockade of his home by security forces for several weeks, as well as other incidents.
State television has shown footage of what the interior ministry said were confessions by Hashemi's bodyguards to planning and carrying out terror attacks, and receiving funding and support from the vice president.
Biden "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," the White House statement added.