At least 184 people were killed on Friday when Islamist militants set off a bomb and opened fire on people attending prayers at a mosque in Egypt’s restive northern Sinai, state media said. Egypt has declared three days of mourning after the attack, state television has said.

No group claimed responsibility for the assault but it was the deadliest yet in the region where for three years Egyptian security forces have battled an Islamic State (IS) insurgency that has killed hundreds of police and soldiers.

State media showed images of bloodied victims and bodies covered in blankets inside the Al Rawdah mosque in Bir al-Abed, west of the city of El Arish. At least 184 people died and another 120 people were wounded, the state news agency MENA reported.

“They were shooting at people as they left the mosque,” a local resident whose relatives were at the scene told Reuters. “They were shooting at the ambulances too.”

Arabiya news channel and some local sources said some of the worshippers were sufis, who hardliners such as IS regard as apostates because they revere saints and shrines, which for Islamists is tantamount to idolatry.

President Abdel Fattah al-Sisi, a former armed forces commander who presents himself as a bulwark against Islamist militants in the region, convened an emergency security meeting soon after the attack, state television said.

Escalating attacks

Militants have mostly targeted security forces in their attacks since bloodshed in the Sinai worsened after 2013 when Mr. Sisi, then an armed forces commander, led the overthrow of President Mohamed Mursi of the Muslim Brotherhood.

But jihadists have also targeted local Sinai tribes that are working with the armed forces, branding them traitors for cooperating with the army and police.