Biden and Kadhemi "welcomed the return of security to the streets, and called on all Iraqi leaders to engage in a national dialogue to forge a common way forward consistent with Iraq's constitution and laws," a White House statement said.

Biden praised Kadhemi's "personal leadership" and his efforts to "de-escalate tensions in the region through dialogue and diplomacy."

The US leader also voiced support for "a sovereign and independent Iraq" amid the strong influence of Iran in the country invaded by the United States in 2003.

Iraq, which has been dominated by sectarian politics since the United States toppled dictator Saddam Hussein, has been without a government since October elections amid tension between powerful Shiite cleric Moqtada Sadr and pro-Iran factions.

Kadhemi had in mid-August called for a national dialogue involving main political leaders, although Sadr did not agree to participate.

Tensions escalated sharply Monday when Sadr said he would quit politics, with his supporters storming an area in Baghdad's high-security Green Zone in violence that killed 30 people.