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 denied terror charges lodged against him the day after US troops left Iraq. Biden "stressed the urgent need for the prime minister and the leaders of the other major blocs to meet and work through their differences together," the White House said in a statement.