CAIRO -- The death toll in an attack on Friday on a mosque in Egypt's North Sinai province rose to 235, official news agency MENA reported.

At least 120 others were wounded when suspected militants attacked the mosque, the report said. Earlier report said at least 155 people were killed in the attack.

An explosive device planted outside the mosque near Arish city went off, before militants opened fire at the prayers, an official security source told Xinhua.

The attack occurred in the village of Rawda in Beir el-Abad, 40 km from Arish, the source added.

Some 50 ambulances rushed to the scene after the attack. Most of the wounded were transferred to the Arish Hospital for treatment.

Egyptian President Abdel-Fattah al-Sisi will chair a meeting of the security committee on the attack, MENA quoted presidential sources as saying.

The meeting will be attended by the ministers of defense and interior in addition to the heads of general intelligence and military intelligence services, the report said.

The Egyptian presidency declared a three-day mourning across the nation.

Grand Imam of Al Azhar Ahmed el Tayeb denounced "the terrorist attack," stressing the importance of working to eliminate terrorists.

Head of the European Union (EU) Delegation to Egypt Ambassador Ivan Surkos also condemned the attack.

"Media bringing news on attack against mosque during today's Friday prayers in Rawda, northern Sinai, reporting many injured," Surkos tweeted.

"I condemn this barbaric terrorist act against innocent civilians," he added.

Egypt is suffering a wave of terrorist attacks, mostly centered in Sinai where militants have killed hundreds of police and soldiers since the army-led ouster of Islamist President Mohamed Morsi in 2013.