The suicide bombing that struck Kabul on Tuesday killed at least 64 people, Afghan officials have announced — more than double the number of deaths initially announced by police.

The blast, for which the Taliban claimed responsibility, struck Afghanistan's capital city around 9 a.m. local time, during the morning rush hour. Hundreds of people were wounded.

It was the deadliest single such incident in Kabul since 2011, Reuters reports. The wire service says that according to Afghanistan's interior ministry, most of the victims were civilians.

As we reported yesterday, the attack involved a suicide bomber in a car and a prolonged exchange of gunfire. The bomb was unusually large, and the detonation could be heard for miles.

The assault targeted an elite security unit that protects government ministers and other high-ranking VIP officials. It came a week after the Taliban announced the start of a spring offensive.

Although Kabul is one of the world's most fortified cities — NPR's Philip Reeves describes it as "a cluster of forts, wrapped up in razor wire and concrete blast barriers, patrolled by a multitude of hard-faced men with guns" — the suicide bomber somehow managed to drive a bomb into the city's center.

Philip spoke to a witness Tuesday. Here's an excerpt of his report:

"We're beside the Kabul River. It runs through the middle of Afghanistan's capital. Bahram Hakimi has come here to squat on a wall, smoke a cigarette and gaze at the brown water rushing by. He says he hopes this will calm him after the terrible experience he went through a few hours earlier a few hundred yards from here."Hakimi says he was asleep in his car when the bomb detonated. The blast was so strong, it knocked him out and shattered all his car windows."Hakimi says once he came to his senses and discovered that, amazingly, he wasn't hurt, he helped several of the hundreds of injured get away from the carnage. Hakimi is young, just 21. As he stares down at the river rushing by, he's full of gloom about his country's future." 'Afghanistan is clearly heading for disaster,' he says."Copyright 2016 NPR. To see more, visit