CAIRO — A powerful explosion tore through a security headquarters in a city northeast of the capital early Tuesday, killing at least 13 people and injuring more than 100 others, state media reports said.
Egyptian authorities described the attack in the Nile Delta city of Mansoura as the most serious of its kind since the military-backed government took power almost six months ago. Deadlier strikes have taken place in the Sinai Peninsula, where Egyptian troops are battling an Islamic insurgency, but there had not yet been an attack on this scale in an urban area close to Cairo.
There was no immediate claim of responsibility, but Egypt’s prime minister, Hazem Beblawi, called it a terrorist act. Officials swiftly cast blame on Islamist groups, and expressed determination to go ahead with next month’s scheduled referendum on the country’s new constitution.
The attack occurred a little after 1 a.m., when many people are typically still out in the streets in Egyptian cities. Television showed floodlighted scenes of large crowds gathered outside the security building, part of its facade sheared off, while medical personnel worked frantically to treat injured and searchers began gingerly removing slabs of the wreckage.
The blast set cars ablaze and damaged nearby buildings. Twisted metal and broken glass littered the surrounding area.
At least eight of the 13 confirmed dead were identified by authorities as police officers, and the others either civilians or unknown. Officials cited by state media had initially put the death toll at 14, and hours later, rescuers were still looking for bodies or survivors among the rubble.
In the months since Islamist president Mohamed Morsi was removed from power in a popularly supported army coup, attacks against security forces have become commonplace in the restive Sinai Peninsula, and in and near the Suez Canal city of Ismilia.
In September, the interior minister escaped an assassination attempt by suicide bomb in Cairo. A Sinai-based militant group known as Ansar Bayt al-Maqdis claimed responsibility for that attack. The same group this week threatened more attacks on Egypt’s security forces, and urged police and soldiers to desert the ranks.
Mansoura has been the scene of frequent protests by supporters of the Muslim Brotherhood, calling for Morsi’s reinstatement.