Casualties in bomb blast near Egypt's foreign ministry Published duration 21 September 2014

media caption The BBC's Orla Guerin visited the scene of the blast

A bomb explosion near the Egyptian foreign ministry in Cairo has killed at least two police officers, security officials say.

The blast occurred on a crowded street near the River Nile. Witnesses said smoke was seen rising from the area.

No group has so far claimed responsibility for the explosion.

Islamist militants have intensified attacks on the security forces since the army ousted President Mohamed Morsi of the Muslim Brotherhood in 2013.

Sunday's blast occurred in the Bulaq Abu-al-Ila district.

The bomb is believed to have been planted below a tree.

Initial reports said at least four people - two policemen and two civilians - were killed.

Security officials later sealed off the area, looking for more bombs, Egypt's Mena news agency reports.

The Islamist violence at first targeted mostly police and the army in the Sinai peninsula, but has recently spread to other regions including the capital.