KABUL, Afghanistan (AP) – A bomb ripped through a police bus in a crowded civilian area in Kabul on Sunday, killing more than 35 people, officials said, in what appears to be the deadliest attack in the capital since the fall of the Taliban.

The police academy bus was carrying several police recruits when the bomb went off inside it, leaving several dead, said Zalmai Khan, the deputy police chief of Kabul province. At least 35 people were also wounded.

The thunderous explosion was heard throughout central Kabul at about 8:10 a.m. local time.

Ali Shah Paktiawal, Kabul police director of criminal investigation, said more than 35 people were killed, including policemen and civilians. He said dozens were wounded and sent to nearby hospitals.

Fazel Rahim, a doctor from a nearby hospital, said 18 dead bodies lay in the hospital courtyard, while more than 35 wounded were being treated inside the building.

“Most of the wounded are in serious condition,” said Mr. Rahim, whose hands and white coat were covered in blood.

The roof of the bus was blown off and officers were pulling a number of bodies from the wreckage, according to an Associated Press reporter at the scene.

The explosion twisted the bus into a charred skeleton, and bloody unidentifiable body parts littered the area as far as 30 yards from the bus. Hundreds of police and investigators were inspecting the scene.

The explosion appears to have happened in the front of the bus, which was more badly damaged than the rest of vehicle. Officials were trying to determine if it was a suicide attack or a bomb planted on the bus.

Wali Mohammad, an eyewitness who was driving his car just behind the bus, said “there were a lot killed and wounded, both police and civilian.”

Mr. Mohammad said that he “saw a big fire and dust in front of me.”

The blast happened at a crowded bus station, used by both police and civilians, near the Kabul governor’s house.

Police and other Afghan security officials are commonly targeted by insurgents, who consider them tools of the U.S.-backed government of President Hamid Karzai.

At least 307 Afghan security officials have been killed in violence so far this year through June 15, according to an Associated Press tally of figures from American, U.N., NATO and Afghan authorities.

The attack appears to be the deadliest attack in Kabul since the fall of the Taliban. Last September, a suicide bomb attack left 16 dead, including two American soldiers close to the American embassy in the capital. Days later, a suicide attack near the Interior Ministry left 12 people dead and over 40 others wounded.