A suicide bomber has struck a heavily policed district of Damascus, killing at least seven people according to state television.

Such attacks are rare in the Syrian capital, the bastion of President Assad’s government as the conflict nears its sixth anniversary.

Several more people who were wounded are said to be in a critical condition and the death toll is expected to rise.

State TV quoted a police source as saying the bomb went off in the Kafr Sousa neighbourhood where some of Syria’s main security installations are located.

The report said it happened near a sports club, giving no more details.

The opposition monitoring group the Syrian Observatory for Human Rights – which is based abroad but has a wide network of contacts inside the country – has spoken of eight fatalities, saying four soldiers including a colonel were among the victims.

Part of the district is home to government ministries and and intelligence headquarters, but the attack is said to have happened in a different sector.