Two car bombs ripped through a crowded street in front of the Interior Ministry in central Baghdad on Thursday, killing 18 people and wounding three dozen others. Al Qaeda in Iraq (search) said it carried out the attack, the bloodiest in more than a month.

In a statement posted on the Internet, the group, headed by Jordanian-born militant Abu Musab al-Zarqawi (search), said the attack targeted a patrol outside the office of Interior Minister Falah al-Naqib (search), who is in charge of the nation's police. The claim could not be independently verified.

Al-Naqib was in his office at the time of the explosions, but was not injured. He came out afterward to examine the scorched road and blackened rubble left by the blast. The ministry building, built by Saddam Hussein's (search) government to survive major attacks, was not damaged.

Meanwhile, a new video broadcast on al-Jazeera television showed a man who identified himself as a Pakistani diplomat kidnapped last weekend in Baghdad. The Arab satellite station said the man, who was wearing a white skull cap, urged the Pakistani government and international community to intervene and secure his release.

The station said the kidnappers, identified as being from the previously unknown group Amuriya Brigade, made no demands for his release.

Malik Mohammed Javed, deputy charge d'affaires at the Pakistani mission in Baghdad, was last seen Saturday leaving his home for prayers at a mosque. The Pakistani Foreign Ministry earlier said the Omar bin Khattab group claimed responsibility and demanded money for his release. The video broadcast Thursday couldn't be independently verified and the discrepancy between the groups' names couldn't be explained.

The death toll from Thursday's car bombs was the highest from an explosion since March 10, when a bomber blew himself up at a Shiite mosque during a funeral, killing 47 people.

The force of Thursday's attack threw people to the ground and sent thick black smoke billowing over the city.

Ali Ahmed, 28, said he was selling ice cream when he heard an explosion, followed by gunfire and another explosion.

"My stall was partially destroyed because of this terrorist act," he said. "Some people have lost their lives. As for me, I have now lost my source of income."

Abdullah Hussein Zamel was cleaning tables at a restaurant near the heavily fortified Green Zone when the blast shattered the windows.

"I went outside and saw dead and injured people," he said. "After that, I heard police open heavy fire on a second car."

Panicked students from a nearby secondary school and university gathered in the street, some weeping.

"We are terrified," said Hoda Raheem Hadi, a 22-year-old computer science student. "Why is this happening?"

After clearing the area, U.S. forces set off a third car bomb that apparently failed to explode earlier. Nobody was injured in that blast.

Interior Ministry official Capt. Ahmed Ismael said the first two blasts killed 18 people and wounded 36.

It was the latest attack claimed by Al Qaeda in Iraq. On Tuesday, the group claimed responsibility for bloody clashes with U.S. soldiers in the Syrian border town of Qaim, and on Wednesday it claimed an attack on a U.S. convoy that killed five Iraqis and wounded four U.S. contract workers on Baghdad's airport road. None of the claims could be verified.

In northern Iraq, seven gunmen riding in two vehicles fired on the police station just south of Kirkuk shortly after dawn, killing five police officers and one civilian, police Brig. Sarhat Qadir said.

Militant group Ansar al-Sunnah claimed responsibility in an Internet posting, and said it had teamed up with Zarqawi's Al Qaeda in Iraq for an attack Wednesday in Kirkuk — an unusual mention of cooperation among Iraq's disparate and sometimes competing militant groups.

The Web posting, which couldn't be independently corroborated, said an explosive device that killed 12 police Wednesday was composed of three bombs buried under a decoy device — a lure to draw policemen to the blast site.

A bomber also blew himself up near an Iraqi police checkpoint in Mahawil, 50 miles south of Baghdad, killing four policemen and wounding six others, the Polish-led military force said.