Beirut blast: judge questions security chiefs as third minister resigns

Investigation focusing on why chemicals were stored at port for six years despite warnings

A Lebanese judge has begun questioning the heads of the country's security agencies over last week's devastating blast in Beirut, as another cabinet minister resigned in protest.

Judge Ghassan El Khoury began by questioning Maj Gen Tony Saliba, the head of state security, according to the state-run National News Agency. It gave no further details, but other generals are scheduled to be questioned.