U.S. Vice President Joe Biden continued his talks Monday with Iraqi leaders in a bid to urge them to end the political deadlock over forming a new government after four months of the country's parliamentary elections.

During the final day of his surprise visit, Biden was expected to meet with Iraqi President Jalal Talabani, a day after he held separate talks with Prime Minister Nuri al-Maliki and his rival former Prime Minister Ayad Allawi, during which he stressed his country's support for democracy in Iraq.

In a statement issued by Maliki's office after his meeting with Biden, Maliki confirmed that talks among Iraqi political blocs are underway and he expected they would agree on the distribution of main government posts before the date of the next parliamentary session due to be held on July 14.

The statement also stressed on the "significance of all Iraqi parties participating in the new government."

Government spokesman Ali al-Dabbagh said during the two-hour meeting, Biden expressed his country's concern about the delay of forming the new government.

Late on Sunday, a statement by Allawi's Iraqia List obtained by Xinhua said that "Allawi reviewed with Biden the talks carried out by the Iraqia bloc with the other political blocs, stressing the right of the list as the vote-winner to form the next government according to the constitution."

Earlier Sunday, at one of former Iraqi leader Saddam Hussein's palaces, Biden and his wife officiated an Independence Day naturalization ceremony in honor of 156 service members who earned their U.S. citizenship through service.

"This nation, once embroiled in sectarian strife and violence, is moving toward a lasting security and prosperity with a government that represents the interest of every member of the community in Iraq," Biden told a crowd of U.S. service members, according to a press release from the U.S. military obtained by Xinhua.

"When the new government is formed, it will mark something absolutely extraordinary: a peaceful transition of power encompassing all the people of Iraq," he added.

On Saturday, Biden arrived in Baghdad on an unannounced visit for two missions: to celebrate the July 4 weekend with U.S. troops and put pressure towards the formation of an Iraqi government.

Biden's visit came amid ongoing political deadlock over the formation of the next government nearly four months after the country's parliamentary polls.

Nearly four months after the war-torn country held its landmark parliamentary elections, Iraqi political leaders are still wrangling over who will head the next government, leaving the formation of the new government in a deadlock.

The U.S. forces last year have pulled out of Iraqi cities and are working to formally end combat operations by September 1.