Iraq's PM al-Maliki speaks during one of several planned ceremonies to mark the end of American military presence in Iraq, in Baghdad
Iraqi Prime Minister Nuri al Maliki has threatened to resign, as observers fear that the coalition government is on the brink of collapse.

Iraqi Prime Minister Nuri al Maliki has threatened to resign if the parliament does not pass a no-confidence vote against deputy minister Saleh al Mutlaq.

The move comes a day after the government issued an arrest warrant for vice president Tareq al Hashemi.

The Al Arabia website reported the latest developments on Tuesday, relating that Mr Mutlaq had allegedly called the government of Mr Maliki a "dictatorship".

Mr Maliki, in turn, asked parliament for the vote against Mr Mutlaq after he accused the Sunni leader of "lacking faith in the political process".

Leading up to this impasse, on Monday Mr Maliki, a Shiite, ordered that an arrest warrant be issued for Mr Hashemi, who is also a Sunni, accusing him of running a hit squad that killed government officials and promoting sectarian violence.

Mr Hasemi denied the claims and issued a counter-attack against the government, accusing it of attempting to discredit him.

"I'm shocked by all these things," Mr Hashemi said from the northern city of Irbil. "I swear to God that al-Hashemi didn't commit any sin or do anything wrong against any Iraqi either today or tomorrow and this is my pledge to God.

"Al-Maliki is behind the whole issue. The country is in the hands of al-Maliki. All the efforts that have been exerted to reach national reconciliation and to unite Iraq are now gone. So, yes, I blame al-Maliki," he added.

Both Mr Hashemi and Mr Mutlaq are members of the Iraqiya bloc, a secular group largely composed of Sunnis, who are one of the minority groups in Iraq.

Following the final withdrawl of U.S. troops from Iraq at the weekend, observers fear that the fragile coalition government, which is divided between Shiite, Sunni and Kurdish blocs of power, is now on the brink of collapse.