A homicide car bomber struck a heavily guarded neighborhood Tuesday near the home of a former Afghan vice president and a hotel favored by Westerners, killing at least eight people and wounding dozens, officials said.

The Afghan Interior Ministry said the target of the bombing was unclear, but security officials at the scene said the bomber was going after the home of former first vice president, Ahmad Zia Massoud. He is the brother of legendary anti-Taliban hero, Ahmad Shah Massoud, who was killed by Al Qaeda two days before the attacks on Sept. 11, 2001.

"Of course we were the target," said Shah Asmat, an aide to the former vice president. "Before, the Taliban killed Massoud. Now, they tried to kill his brother."

Afghan President Hamid Karzai, during a speech he was delivering at a conference on corruption, said two of Massoud's guards were among those killed in the explosion.

Ministry of Interior spokesman Zemeri Bashary said four men and four women died in the midmorning blast. He said about 40 others were wounded.

"It was a suicide attack," Bashary said. "We are investigating. We don't know the target of the attack."

The midmorning blast, in Kabul's congested Wazir Akbar Khan district, slightly damaged the Heetal Hotel, which is owned by the son of Burhanuddin Rabbani, who served as president of Afghanistan from 1992 until 1996.

An Afghan intelligence official in charge of security for the hotel said he did not think the Heetal was the target because the blast occurred about 30 yards (meters) from the entrance. The official declined to be named because he was not authorized to provide information about the blast. The official, who suffered cuts to his face, was standing in the front of the hotel when the explosion occurred.

Three homes nearby were severely damaged and windows in nearby buildings were shattered. A large cloud of dark gray smoke rose from the area as firefighters worked to extinguish flames from the burning vehicle.

A witness at the scene, a 22-year-old English student at Kabul University, reported seeing a black, four-wheel drive vehicle near the hotel.

"It drove very slowly to the checkpoint" of the hotel, said Hamayun Azizi. "And then it blew up."

The explosion flipped the vehicle, which landed upside down about 10 yards (meters) from the blast site, according to a witness at the scene. The blast, which occurred at the entrance to a street leading to the hotel, created a crater, roughly 1 meter deep and 2 meters wide, in the street.

Members of the Afghan National Army and Afghan National Police secured the area.

The explosion was heard a few miles away by about 200 people gathered at the Foreign Ministry for a three-day conference on corruption in the Afghan government. Those at the conference paused for a moment after the blast. After a delay, the event began with Karzai's speech.

Separately, five Afghans and a Nepalese national were killed in an explosion that occurred at a foreign organization operating in Paktia province, said Gen. Azizdin Wardak, police chief of Paktia province in eastern Afghanistan. No other details were available.