CAIRO: An explosion went off Sunday outside a military intelligence building in the countryside northeast of Egypt’s capital, wounding four, military and security officials said.

Security officials said remains of a vehicle were found nearby the building in Anshas, a village in Sharqiya province that houses a number of military facilities, and they are looking into whether the blast, which damaged a wall, was a car bomb. Initial reports suggested that explosion was caused by a hand grenade thrown at the building.

State TV showed footage from the site of the explosion in the rural village, with debris from the damaged wall leaving a big gash in the building. A Sinai-based militant group has claimed responsibility for a Tuesday car bomb at a Nile Delta security headquarters that killed 16, mostly policemen.

State TV reported Sunday that a homemade bomb was found outside the medical school of Al-Azhar University branch in the Nile Delta city of Damietta.

Military spokesman Ahmed Mohammed Ali said on his official Facebook page that the explosion caused damage to the back wall of the military intelligence office in Anshas, and left four soldiers guarding the building injured. He said a probe is under way to determine the cause.