A bomb explosion near a court house in the centre of the Egyptian capital wounded 12 people late Tuesday, security and medical officials said.

A bomb explosion near a court house in the centre of the Egyptian capital wounded 12 people late Tuesday, security and medical officials said.

The blast was caused by a  homemade bomb planted under a metal railing in the crowded district near the Superior Court and a metro station, a security official said.

Militants have killed scores of policemen in bombings and shootings since the military overthrew the Muslim Brotherhood’s president Mohammad Mursi last year. The target of Tuesday's attack was not immediately clear.

Senior health ministry official Khaled al-Khatib told state television that a pregnant woman was among the wounded.

Police cordoned off the area, keeping journalists and a large crowd of onlookers away, as they searched for more explosives.

It was the first serious attack since a bomb outside the foreign ministry headquarters killed two policemen on September 21.

That attack was claimed by a militant Islamist group, Ajnad Misr, which says it targets policemen to avenge hundreds of pro-Mursi protesters killed in clashes with security forces after the president's overthrow.