A suicide bomber has attacked an area near the Russian embassy in the Afghan capital Kabul, officials say, killing at least four people.
Officials say about 20 others have been wounded.
The explosion sent black smoke billowing into the sky, with emergency services rushing to the scene.
No group has claimed responsibility for the blast, but the Taliban will be the main suspects as they have launched attacks on the city in the past.
Tolo News reported that the bomb was detonated by a motorcycle rider who was targeting a civilian bus in the west of the city.
However, Interior Ministry spokesman Sediq Sediqqi was quoted by the Associated Press as saying that the explosion was caused by a car bomb.
The latest incident follows recent attacks near the Indian, Pakistani and Italian missions in Afghanistan.
Last week at least seven Afghan security personnel were killed in a gun battle near the Pakistani consulate in Jalalabad.
Observers have speculated that the attacks could be aimed at destabilising attempts to revive peace talks with Taliban, but there is no confirmation.