Islamist militants killed 12 members of Egypt's military in North Sinai province and wounded six more in an attack on a checkpoint on Friday, the military said, adding that it killed 15 militants in return.
ISIS claimed responsibility for the incident, which took place 40 kilometers (25 miles) from the town of Bir al-Abd, making it the first major attack in the central Sinai area, which had so far escaped the militant Islamists' campaign.
It was carried out using assault rifles and some heavier weapons, medical and security sources said. The wounded were taken to hospital in al-Arish.
"An armed group of terrorist elements attacked a security checkpoint in North Sinai this morning using four-wheel drives and were immediately engaged. Our forces killed 15 terrorists," the military said in a statement. "The clashes led to the martyrdom of 12 and injury of six armed forces heroes."
ISIS said it killed more than 20 soldiers and that it suffered no casualties. It said its members looted weapons and ammunition from the checkpoint.
"A number of the caliphate's soldiers have launched an attack on a checkpoint belonging to the apostate Egyptian army south of Bir al-Abd that killed over 20 apostates and injured more," the group said in a statement.
An Islamist insurgency in the rugged and thinly populated Sinai Peninsula gained pace after the Egyptian military overthrew Egyptian President Mohamed Morsi of the Muslim Brotherhood, Egypt's oldest Islamist movement, in mid-2013 following mass protests against his rule.
The militant group staging the insurgency pledged allegiance to ISIS in 2014 and adopted the name Sinai Province. It is blamed for the killing of hundreds of soldiers and policemen, and has started to target Western targets within Egypt.
Egyptian President Abdel Fattah al-Sissi, the former military chief who led the overthrow of Morsi, describes Islamist militancy as an existential threat to Egypt, an ally of the United States. ISIS controls large parts of Iraq and Syria and has a strong presence in Libya, which borders Egypt.
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