BAGHDAD — A wave of car bombings hit the Iraq capital on Tuesday, killing 14 people and wounding more than 70 as violence surges in the country amid an escalating political crisis a month after the U.S. military withdrawal.

At least 170 people have died in attacks since the beginning of the year, many of them Shiite pilgrims attending religious commemorations. The last American soldiers left the country Dec. 18.

Suspected Sunni insurgents have frequently targeted Shiite communities and Iraqi security forces to undermine public confidence in the Shiite-dominated government and its efforts to protect people.

Tuesday's first attack targeted an early morning gathering of day labourers in Baghdad's Sadr City neighbourhood. Police said eight were killed and another 21 wounded. Minutes later, an explosives-packed car blew up near a pastry shop in the same district, killing three people and wounding 26, police said.

Later in the morning, two more explosives-laden cars detonated, killing three and wounding 29 people.

A parked car bomb exploded near a high school at 10:30 a.m. in the predominantly Shiite neighbourhood of Shula in northern Baghdad, killing two students and wounding 16 others, most of them also students, according to local police.

In the neighbouring district of Hurriya, one person was killed when an explosives-packed car, parked along a busy commercial street detonated five minutes after the Shula blast, police officials said. Thirteen people were injured in that bombing.

Hospital officials in Baghdad confirmed the death toll. All officials spoke on condition of anonymity because they were not authorized to talk to the media.

While insurgents have carried out a number of deadly attacks in recent years, there is little indication so far that the country is slipping back toward the widespread sectarian bloodshed of 2006 and 2007.

Nonetheless, these recent attacks are seen as particularly dangerous because they coincide with both the departure of U.S. troops, as well as a political crisis pitting Shiite officials against the largest Sunni-backed bloc.

The political battle erupted last month after the Shiite-led government issued an arrest warrant against the Sunni vice-president, Tareq al-Hashemi, on terrorism charges, sending him into virtual exile in the Kurdish autonomous region in northern Iraq. In protest, al-Hashemi's Sunni-backed Iraqiya bloc has been boycotting parliament and Cabinet sessions, bringing government work to a standstill.

Sunnis fear that without the American presence as a last-resort guarantor of a sectarian balance, the Shiite government will try to pick off their leaders one by one, as Prime Minister Nouri al-Maliki tries to cement his own grip on power.

Last week, the leader of the Sunni-backed Iraqiya bloc, Ayad Allawi, accused al-Maliki of unfairly targeting Sunni officials and deliberately triggering a political crisis that is tearing Iraq apart. Allawi, who is a Shiite, said Iraq needs a new prime minister or new elections to prevent the country from disintegrating along sectarian lines.