Egypt's military and police forces have killed 52 militants and arrested dozens of suspects in an ongoing crackdown in Sinai, the army said in a statement on Sunday.

Thirty-nine "very dangerous takfiris" were killed by military forces in different raids in central and northern Sinai and 13 others were killed by national security forces in the North Sinai capital of Arish, military spokesman Colonel Tamer El-Refaie said in a video showing footage and photos of the operation which was published on his offical Facebook page.

The statement said the militants were killed over the past few days.

The attacks are part of a major security operation, Operation Sinai 2018, which was launched in February to target terrorists in Sinai, the Nile Delta and the country's Western Desert. The months-long campaign involves the army, navy, air force and police.

The Arabic word "takfiri" refers to hardline Sunni Muslims who accuse other Muslims of being infidels, often as a justification for using violence against them.

The air force, which has been conducting airstrikes in northern and central Sinai since the operation started, has destroyed 15 vehicles loaded with weapons and ammunition while attempting to infiltrate through the country's western border with Libya. Seventeen other vehicles were destroyed south of Cairo, the spokesman added.

Fourty-nine suspects were arrested and 26 hideouts and caches used by the militants were destroyed during raids by military and civil police forces in north and central Sinai.

Military engineers have discovered and destroyed 64 bombs planted to target forces at operation sites. Forces also destroyed four tunnel openings in the border city of Rafah in North Sinai.