Afghan police say a suicide attack has taken place outside the Iraqi embassy in the capital, Kabul.
Gunfire was heard following several explosions in the central Shar-e-Naw neighbourhood.
A gun battle is said to be under way and civilians are being evacuated from the area.
Kabul has seen a number of deadly attacks this year blamed on the Taliban or so-called Islamic State. Details of the latest incident are unclear.
One security official is quoted as saying a suicide bomber targeted the area housing a police headquarters and the Iraqi embassy compound.
Pictures on social media show black plumes of smoke rising into the sky.
It is not yet known whether anyone has been hurt.
According to the United Nations, the country has seen at least 1,662 civilian deaths in the first half of the year, with about 20% of those in the capital.
Last Monday a suicide car bomb killed at least 30 people in a mainly Shia district of Kabul.
On 31 May, a huge bombing in the centre of the city killed more than 150 people, the deadliest militant attack in the country since US-led forces ousted the Taliban from power in 2001.
~ Salvador Dali