Baghdad, Iraq ? Insurgents killed 39 people in a series of rapid-fire attacks Thursday, including three suicide car bombings within an hour and a drive-by shooting at a busy Baghdad market that ratcheted up the bloody campaign to undermine Iraq’s government.

Iraq’s interior minister, meanwhile, claimed the government offensive seeking to root out rebels in Baghdad had scored big gains, saying this week’s sweep by Iraqi soldiers and police captured 700 suspected insurgents and killed 28 militants.

Iraqi and U.S. forces have stepped up operations to answer an insurgent onslaught that has killed at least 814 people since Prime Minister Ibrahim al-Jaafari announced his Cabinet five weeks ago, but militants staged deadly attacks across a swath of northern Iraq.

In Tuz Khormato, a popular highway stop 55 miles south of the oil-rich town of Kirkuk, a suicide car bomber targeted bodyguards for Iraq’s Kurdish deputy prime minister as they ate at a restaurant. The blast killed 12 people.

“I was sitting inside my restaurant when about six cars parked nearby and their passengers came inside and ordered food,” owner Ahmed al-Dawoudi said. “Seconds later, I heard a big explosion and the restaurant was turned into twisted wreckage and rubble. Blood and pieces of flesh were everywhere.”

Earlier in Kirkuk, a suicide car bomber trying to attack a convoy of civilian contract workers killed a young boy and three other Iraqi bystanders and wounded 11 people.

Iraqi security officers check the site of car bomb explosion in Tuz Khormato, about 55 miles south of the northern oil city of Kirkuk. At least 12 people were killed Thursday in a massive explosion targeting the town's restaurant, where bodyguards of Iraq's Kurdish deputy prime minister were eating.

Another suicide bomber killed four people and wounded four in Baqouba, about 35 miles northeast of Baghdad. Hours later, two parked motorcycles rigged with bombs blew up near a coffee shop there, killing five Iraqis and wounding 13.

In the capital, men in three speeding cars sprayed gunfire into a crowded market in the northern neighborhood of Hurriyah, killing nine people, the interior and defense ministries said. Two other attacks in the Baghdad area killed four people and injured three.

As part of the campaign against insurgents, Iraq’s government launched the biggest Iraqi offensive Sunday in Baghdad since Saddam Hussein’s fall two years ago.

Angry leaders of the Sunni Arab minority complained Thursday that their community was being targeted by the crackdown and threatened to boycott the drafting of Iraq’s new constitution – a crucial document U.S. officials hope will help stabilize Iraq.

“I swear by God that we’ll demand none from now on to lay down his weapon,” yelled Osam Al-Rawi, head of the Iraqi teachers union and representative of the influential Association of Muslim Scholars, a Sunni group thought to be close to the insurgency.

However, in a heartening sign, Sunni leaders did not slam the door on al-Jaafari’s efforts to bring them back into the political fold.