KIRKUK, Iraq - Twin suicide car bombings exploded within 20 minutes of each other in Iraq's north on Monday, killing at least 80 people and wounding around 150 in attacks targeting a Kurdish political office and ripping through an outdoor market, police said.

The attacks in Kirkuk began around noon when a suicide bomber detonated his explosives-packed truck near the concrete blast walls of the headquarters of the Patriotic Union of Kurdistan, the party of Iraqi President Jalal Talabani.

The explosion blasts a 30-foot-deep crater in the pavement and collapsed part of the roof of the one-story PUK office. Outside the offices, the burnt shells of more than two dozen vehicles were in the street.

Soon after, the second bomber attacked the Haseer market, 700 yards away, destroying stalls and cars, said Kirkuk police Brig. Sarhat Qadir.

The Haseer market - an outdoor souk with stalls of vegetable and fruit sellers - is frequented by Kurds in Kirkuk, a city where tensions are high between the Kurdish and Arab populations. At least 80 people were killed and around 140 wounded, said police Brig. Burhan Tayeb Taha.

The attack was believed to be the deadliest suicide bombing in Kirkuk - 180 miles north of Baghdad - where violence tends to be on a smaller scale of shootings, roadside bombs and kidnap-slayings, often linked to the struggle between the city's Kurds and Arabs. Monday's blast came just over a week after one of the Iraq conflict's deadliest suicide attacks hit a village about 50 miles south of Kirkuk, killing more than 160 people.

Iraqi officials have said Sunni insurgents are moving further north to carry out attacks, fleeing U.S. offensives in and around Baghdad, including in the city of Baqouba, a stronghold of extremists on the capital's northwestern doorstep. The month-old sweeps, fueled by the "surge" of 28,000 new American troops sent to Iraq this year, aim to pacify the capital and boost the government of Iraqi Prime Minister Nouri al-Maliki.

U.S. troops launched a new offensive south of Baghdad on Monday, aimed at stopping weapons and fighters from moving into the capital, the military said in a statement.

The statement did not say where the new sweep, codenamed Marne Avalanche, was taking place. Cut in recent days U.S. commanders have said they plan new operations to cut off an insurgent supply route southwest of the city, running from western Anbar province. An offensive has been ongoing for the past month in a region southeast of Baghdad.

Violence appears to have eased in Baghdad in recent weeks - but attacks, including deadly car bombs, happen daily.

A string of attacks Monday morning in the capital killed at least 14 people.

In the deadliest, a roadside bomb exploded as an Iraqi army patrol passed in the city's northeast outskirts, killing five soldiers and wounding nine, an army officer said.

Two car bombs struck, one driven by a suicide bomber who struck a police checkpoint on a major road leading to a major Interior Ministry building inside the Green Zone. Two policemen were killed and seven people wounded, a police official said.

A parked car bomb went off in the central district of Karradah on Monday, exploding near Masbah Square, killing one person, wounding three others and leaving nearby shops burned, a police official said. On Sunday, a car bomb went off about a half-mile away, killing 10 people.

Other deaths in Baghdad were caused by mortars, shootings and roadside bombs, according to police officials. On Sunday, 22 bullet-riddled bodies were found dumped in various locations of Baghdad, apparently the latest victims of sectarian violence, police said. All the officials spoke on condition of anonymity because they were not authorized to release the reports.

The military announced Monday that an American soldier died from wounds received the day before by a bombing in Ninevah province, northwest of Kirkuk.

A group of 24 Iranians escaped from detention in an Iraqi police station in the southern town of Badra this week, police in the town said. They broke out Saturday evening, and while four were quickly recaptured, the remainder may have fled across the nearby border, a police officer in the nearby city of Kut said.

The Iranians had been detained on suspicion of illegally entering the country, said the official, speaking on condition of anonymity because he was not authorized to talk to the press. Thousands of Iranians enter Iraq - particularly the Shiite heartland in the south - for pilgrimage and business, but the U.S. also accuses Iran's Revolutionary Guards of organizing Shiite militants into cells and arming them to attack U.S. and Iraqi forces.

Meanwhile, parliament convened on Monday as Iraqi politicians tried to end a pair of boycotts of the legislature - by Sunni legislators and by Shiite lawmakers loyal to anti-American cleric Muqtada al-Sadr - that are holding up work on crucial reforms sought by Washington.