CAIRO (AP) — Egypt's official news agency and a security official say five people killed and scores others injured when a strong explosion rocked a police headquarters in a Nile Delta city north of Cairo.

The Middle East News Agency says the explosion took place at 1:10 morning on Tuesday, at Dakahlia security headquarters in the Nile Delta province of Mansour, causing collapse of parts of the five-floor building. A security official says 5 people were killed and 80 injured.

The official added that initial investigation suggested that a car bomb caused the explosion. He spoke on condition of anonymity because he was not authorized to speak to the press.

The attack comes a day after an al-Qaida inspired group called on police and army to desert or face death.