CAIRO - At least 235 people were killed when gunmen set off a bomb and opened fire at a mosque in Egypt's northern Sinai Peninsula on Friday, state television reported.

The report also said at least 125 people were wounded in the attack.

Egypt's government declared three days of mourning after the attack - one of the country's deadliest in recent memory.

Security officials said four men in four off-road vehicles opened fire on worshippers during Friday prayers at Al Rawdah mosque in Bir al-Abed, about 40 kilometers from the North Sinai provincial capital of el-Arish.

No group had claimed responsibility for the assault.

A tribal leader and head of a Bedouin militia that fights Islamic State extremists said the mosque is known as a place of gathering for Sufis.

The IS group views Sufis as heretics.

State media showed images of bloodied victims and bodies covered in blankets inside the mosque.

Eyewitnesses reported about 50 ambulances ferrying casualties from the scene to nearby hospitals after the attack.

"They were shooting at people as they left the mosque," said a local resident whose relatives were at the scene.

"They were shooting at the ambulances too."

President Abdel-Fattah al-Sisi convened an emergency security meeting soon after the attack. The meeting was attended by the ministers of defense and interior in addition to the heads of general intelligence and military intelligence services, MENA state news agency reported.

IS insurgency

Egypt's security forces have battled an IS insurgency in north Sinai, where extremists have killed hundreds of police officers and soldiers since fighting there intensified over the last three years.

Aside from the IS group, Egypt also faces a threat from al-Qaida-aligned extremists who operate out of neighboring Libya.

Extremists have mostly targeted security forces in their attacks, but have also tried to expand beyond the peninsula by hitting churches and pilgrims.

In July, at least 23 soldiers were killed when suicide car bombs hit two military checkpoints in Sinai Peninsula, an attack claimed by the IS group.

In May, gunmen attacked a Coptic group traveling to a monastery in southern Egypt, killing 29.

Reuters - Afp - Xinhua - Ap