Baghdad: Iraq's government marked its first anniversary on Wednesday in turmoil as its premier urged Kurd officials to hand over the Sunni vice president on terror charges, in a row that has raised communal tension.

Washington has urged calm, but Prime Minister Nuri al-Maliki threatened to replace ministers belonging to the Sunni-backed Iraqiya bloc if they did not end a cabinet boycott, while Vice President Tareq al-Hashemi, currently holed up in the autonomous Kurdish region, rejected claims he ran a death squad.

Lawmakers are also due to consider a call from Maliki to sack Sunni Deputy Prime Minister Saleh al-Mutlak, who has decried the Shiite-led national unity government as a "dictatorship".

All this comes just days after US troops completed their withdrawal from the country, leaving behind what US President Barack Obama described as a "sovereign, stable, and self-reliant Iraq."

"We call for the government of the Kurdistan region to... hand over Hashemi to the justice system," Maliki told a news conference in Baghdad. "We do not accept any interference in Iraqi justice."

Maliki also rejected Hashemi's calls for Arab League representatives to observe the investigation and any questioning, telling reporters, "We gave Saddam a fair trial, and we will give Hashemi a fair trial too," referring to now-executed dictator Saddam Hussein.

He also warned Hashemi and Mutlak's Iraqiya bloc that he would replace the group's nine cabinet ministers if they continued to boycott government sessions.