In this Jan. 8, 2011 file photo, Shia cleric Muqtada al-Sadr is seen during his first public appearance since returning from nearly four years of self-imposed exile in Najaf, south of Baghdad, Iraq. The political party loyal to al-Sadr has called for new elections. Karim Kadim/Associated Press

The political party loyal to radical Shia cleric Muqtada al-Sadr called Monday for the dissolution of Iraq's parliament and new elections in another move that could escalate the country's growing sectarian crisis.

The anti-American Sadrist bloc is a partner in the Shia-dominated government of Prime Minister Nouri al-Maliki. Bahaa al-Aaraji, the head of the Sadrists' bloc in parliament, said the elections are needed because of instability in the country and problems that threaten Iraq's sovereignty.

"The political partners cannot find solutions for the problems that threaten to divide Iraq," he said.

Iraq plunged into a new sectarian crisis last week, just days after the last American troops withdrew at the end of a nearly nine-year war.

The new political crisis has been accompanied by a new wave of attacks on the Iraqi capital by suspected Sunni insurgents linked to al-Qaeda. A suicide bomber set off a car bomb Monday at a checkpoint leading to the Interior Ministry, killing seven people and injuring 32, officials said. Police and hospital officials said the bomber struck during morning rush hour, hitting one of many security barriers set up around the ministry's building.

Al-Maliki is in a political showdown with the country's top Sunni political figure, Vice-President Tariq al-Hashemi, after the government issued an arrest warrant for al-Hashemi on allegations his bodyguards ran hit squads targeting government officials.

The prime minister threatened to form a government without al-Hashemi's Sunni-backed political party, Iraqiya, which is boycotting parliament and mulling whether to pull out of the ruling coalition.

Iraq was dominated by the minority Sunnis under Saddam Hussein until the U.S.-led war that began in 2003 ousted him. Majority Shia have dominated the government ever since, though Americans pushed hard for the inclusion of Sunnis with a meaningful role in the current governing coalition.

Political tensions

Bitter sectarian rivalries played out in 2006-2007 in violence that took Iraq to the brink of civil war and the latest tensions have raised fears of a resurgence of Shia-Sunni violence.

The political crisis taps into resentments that are still raw despite years of efforts to overcome them. The Sunnis fear the Shia majority is squeezing them out of their already limited political role. Shia suspect Sunnis of links to militants and of plotting to topple the Shia leadership.

The Sadrists have played an important role in maintaining Shia domination over government -- their support last year catapulted al-Maliki back to the prime minister's office for a second term.

For the proposal to dissolve parliament to gain traction, it would take the consent of at least 1/3 of parliament, the president and the prime minister or a simple majority of lawmakers. Al-Maliki, who only secured his position after nearly nine months of political wrangling after the last elections, would likely be loath to go through the process again and risk an unfavourable outcome.

Al-Aaraji said the proposal first needs approval of the larger coalition between the Sadrists and al-Maliki's alliance, the two most powerful Shia parties.

A Shia lawmaker loyal to al-Maliki, Kamal al-Saiedi, said the proposal should be studied.

"Forming the current government was not an easy issue, therefore going back in the direction of new elections would be more difficult," he said.