Egypt's Sisi vows fierce action against mosque attack very soon: TV

Egyptian president Abdel Fattah al-Sisi vowed on Friday a "fierce action" will be carried out in response to a mosque's attack in North Sinai province that left at least 235 killed, state-run TV reported.

"The army and police will avenge our martyrs and return security and stability with force in the coming short period," he said in a televised speech.

Egyptian president Abdel Fattah al-Sis [File Photo: IC]

"Such attack is aimed at destroying our unity, but it will steel our resolve to defeat terrorism," he added.

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

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.