A car bomb exploded near Afghanistan's interior ministry in Kabul on Wednesday and then gunmen exchanged fire with members of the security forces, police said, in what appeared to be the latest in a series of militant attacks in the capital.
There was no immediate word on casualties, nor was there any claim of responsibility.
Two loud explosions and gunfire were heard coming from the vicinity of the ministry compound and police officials inside said they believed it was a militant attack.
A senior police official said a car bomb was detonated near the ministry's entrance and then a gun battle between attackers and members of the security forces broke out.
A series of deadly attacks in Kabul this year have killed and wounded hundreds of people.
Security in and around Kabul has been on high alert in recent days with more checkpoints and patrols as the government warned of "complex attacks" by the Taliban on the government or foreign installations in coming weeks.
Provincial cities have also been hit as the Taliban, seeking to reimpose hardline Islamic rule, have stepped up fighting across the country since they announced the beginning of their annual spring offensive in April.
The latest violence coincided with a US government report that found few signs of progress in Afghanistan this year, with fighting spreading and hundreds of casualties from militant attacks.
Security officials say violence is expected to pick up as preparations continue for parliamentary elections scheduled for October.