Large car bomb hits central Cairo

A car bomb has exploded outside the police headquarters in Egypt's capital, killing four people and wounding 51, Egypt's health ministry says.

The powerful blast was felt across Cairo and black smoke could be seen rising over the city centre.

A second explosion was later heard in the city's Dokki district.

The blasts come on the eve of the third anniversary of the 2011 uprising that led to the removal of the country's decades-long ruler Hosni Mubarak.

No group has said it was behind the attacks.

They came a day after five policemen were shot dead by two gunmen on motorcycles at a checkpoint in Beni Suef province, south of Cairo.

There was extensive damage to the large concrete building with debris strewn across the street.

The nearby Islamic museum and the National Archives building were also damaged.