The militants killed 12 Egyptian soldiers in a sustained attack on the checkpoint in the Sinai Peninsula on Friday; 15 militants were also killed in the firefight, according to the Egyptian military.

The attack occurred about 50 miles (80 kilometers) east of the Suez Canal near the town of Bir el-Abd, where the wounded were initially treated before being taken east to the city of el-Arish. It is the first major attack in the central Sinai area, which had so far escaped a campaign of Islamist attacks.

An army spokesman issued a statement saying that soldiers clashed with the attackers - who opened fire with machine guns and heavier weapons - in the north of the peninsula. 

"Terrorist elements attacked a checkpoint in the northern Sinai. The clashes left 12 soldiers dead and wounded six others," the statement said. It added that "15 terrorists were killed." Other reports said that as many as eight were wounded.

No group has claimed responsibility for the attack, but  it appeared to bear all of the hallmarks of the local Islamic State (IS) affiliate. The "Emirate of Sinai" is leading the insurgency in a strategic region that borders Egypt and the Gaza Strip, which is ruled by Hamas.

Surge in violence, kidnappings

The attack is the latest in a surge of assaults launched by militants amid a wave of kidnappings and subsequent killings of locals on the peninsula, accused of collaborating with Egyptian forces that are fighting the jihadists.

Simultaneously there has been a considerable decline in the number of IS attacks across the Egyptian mainland.

However, a previously unknown group, named "Hasm," or "Decisiveness," has claimed responsibility for a recent spate of assassination attempts in Cairo, involving a prominent prosecutor, a chief theologian and a former mufti.

Militants in the Sinai have long been a thorn in the side of the Egyptian government, but the insurgency has grown deadlier since 2013, when the military toppled the elected Islamist president in a coup.

Travel is now severely restricted across the Sinai. Foreign journalists seeking a first-hand account of what is going on there are frequently denied government-sanctioned access to the sprawling desert.

President Abdel Fattah al-Sisi, the former military chief who led the overthrow of Islamist President Mohammed Morsi, describes Islamist militancy as an existential threat to Egypt, which is a United States ally.

IS has lost a lot of territory in Iraq and Syria this year, but they still control large areas of Iraq and Syria, and they have a strong presence in Libya, which borders Egypt.

bik/jm (Reuters, AP, AFP, dpa)