A suicide car bomber targeted a convoy of foreign troops in the Afghan capital during rush hour-traffic on Sunday, an official said, flipping an armored vehicle on its side, but the number of casualties was unknown.
Taliban insurgents claimed responsibility for the attack in the city center that broke a period of relative calm in Kabul after a series of bombings in August.
TV footage showed an armored vehicle on its side as Afghan security forces cordoned off the street in the Joi Sheer neighborhood.
"It was a suicide bombing against a foreign forces convoy in a crowded part of the city and there are casualties," said Najib Danish deputy spokesman for the interior ministry.
Danish did not specify whether there were casualties among the foreign forces.
The U.S.-led Resolute Support military coalition in Kabul confirmed that one of its convoys was struck by a bomb. "No casualties are reported at this time," said spokesman Colonel Brian Tribus.
The Taliban insurgents fighting to topple the foreign-backed Kabul government claimed responsibility for Sunday's attack, saying it killed a number of foreign troops.
The group typically inflates casualty figures they inflict on Afghan and coalition forces.
The attack came during a period of heightened tension following intense fighting between government troops and the Taliban around the northern city of Kunduz, which fell briefly to the insurgent Islamist movement at the end of last month.
Fighting between government forces and the Taliban continues on the outskirts of Kunduz.