Iraqi officials say bomb attacks in the capital and in the south have killed at least 57 people and wounded more than 130 others.

The deadliest attack Thursday hit the southern city of Nasiriyah, where an explosion targeting pilrgims killed 30 people.

Earlier in Baghdad, a pair of blasts hit the northern neighborhood of Sadr City. Officials say a bomb planted in a motorcycle exploded near a group of laborers who had gathered to seek work, followed by a roadside bombing a short time later. The explosions killed 12 people.

Later in Kazimiyah, another Shi'ite area in northern Baghdad, a pair of car bombings killed 15 people.

The violence Thursday come two weeks after a string of bombings killed at least 69 people across the capital. Those attacks followed the withdrawal of the last U.S. troops from Iraq amid increased political tensions in the country.

Prime Minister Nouri al-Maliki's Shi'ite-led government issued an arrest warrant last month for Sunni Vice President Tariq al-Hashemi, who has denied charges that he ran a death squad and has fled to the Kurdish north to avoid detention.

The Sunni-backed Iraqiya coalition has boycotted parliament and the Cabinet, with leaders of the country's Sunni minority complaining that Mr. Maliki is monopolizing power in the hands of Shi'ites and excluding Sunnis from decision-making.