No militant group immediately claimed responsibility for the attack
A powerful blast hit the centre of Afghanistan's capital Kabul on Tuesday, Reuters reporters said.
The explosion occurred near the diplomatic quarters and a busy market square where there are many government buildings, including the presidential palace, as well as a number of embassies and offices of international media and aid agencies.
Clashes between Afghan forces and the Taliban have intensified across the country with the insurgent group gaining control over check points, trading posts and infrastructure projects.
No militant group immediately claimed responsibility for the attack.