Pakistan has detained several people in the attempted assassination of the man selected to be the country's prime minister, a government minister said Sunday.

Others close to the investigation also said it was making progress, including a senior official who said the bomber's head had been discovered, along with what appears to be tatters of his clothing.

The clothing included a tag from a tailor in Attock, the main town near the site of Friday's suicide attack. The tailor was being questioned, said the official, who spoke on condition of anonymity.

Shaukat Aziz (search), the finance minister tapped to take over as prime minister, escaped unharmed, but nine people were killed and three dozen wounded. Among the dead was Aziz's driver, an indication of how close the bomber came.

In a statement Saturday on an Islamic Web site, a militant group calling itself the "Islambouli Brigades of al-Qaida" said it was behind the blast.

"One of our blessed battalions tried to hunt a head of one of America's infidels in Pakistan while he was returning from Fateh Jang, but God wanted him to survive," said the Arabic-language statement.

It said the attack was in response to President Gen. Pervez Musharraf (search)'s handing of captured militants to the Americans. "This operation yesterday will be followed by a series of painful strikes if you don't stop what you are doing by complying to the wicked (U.S. President) Bush's orders," the group said, addressing Musharraf.

The group said its message was "the last warning" and that "within the coming few days, our brigades will speak with the language of blood which is the only language you understand."

It was impossible to verify the authenticity of the claim. Lt. Khaled Islambouli was the leader of the group of soldiers who assassinated Egyptian President Anwar Sadat during a military parade in Cairo in 1981.

Information Minister Sheikh Rashid Ahmed (search) told The Associated Press that security officials investigating the attack on Aziz "have made some progress" and have arrested some people. He would not say how many, or whether any of them were considered suspects.

Ahmed has said that the attack bore the fingerprints of al-Qaida. Osama bin Laden's terror network has already been blamed for two attempts to kill Musharraf in December, ione of which killed 17 people.

Musharraf has been a top U.S. ally in the war on terror, infuriating Muslim radicals in Pakistan and elsewhere, and his security services have arrested a number of top al-Qaida-linked figures, most recently Ahmed Khalfan Ghailani.

Ghailani, a Tanzanian who faces a possible death sentence in the United States for his role in the 1998 twin embassy bombings in East Africa, was nabbed July 25, but his arrest was not announced until Friday, hours before the attempt on Aziz.

The government said the arrest of Ghailani in the eastern town of Gujrat was "a major blow" to al-Qaida and vowed to keep hunting terrorists. Pakistan has already said it would consider extraditing Ghailani to the United States, where he could face the death penalty.

Aziz was tapped by Musharraf to take over as prime minister, but he must first win a seat in parliament before he can take the position. When the attack occurred, he was in the town of Fateh Jang, 35 miles southwest of Islamabad, campaigning in a by-election.

Pakistani television showed gruesome footage of Friday's bombing, with the camera capturing the suicide attacker approaching the driver's door of Aziz's armored Mercedes, raising his hand and then blowing up. Aziz was already in the car, but the driver had not closed his own door yet and was among those killed.

Al-Qaida No. 2 Ayman al-Zawahri called for Musharraf's assassination in a tape released earlier this year, and several homegrown militant groups also have been implicated in plots to kill him.