No group has so far claimed responsibility for the attack but a militant group Ansar Bayt al Maqdis, which has pledged allegiance to Daesh, frequently carries out similar attacks in the Sinai Peninsula.
At least eight Egyptian soldiers were killed in a car bomb attack in northern Sinai, Egypt's army said on Thursday.
"A group of armed terrorists attacked one of the security checkpoints in north Sinai," the army spokesman said.
"A car bomb attack, the clashes that ensued and a blast targeting one of the vehicles left eight members of the armed forces dead," he added.
Three militants were also killed in the fighting, he said.
There was no immediate claim of responsibility for the attack.
But a militant group Ansar Bayt al Maqdis, which has pledged allegiance to the Daesh terrorist organisation in 2014, frequently carries out similar attacks in the Sinai Peninsula.
The group intensified its campaign against the Egyptian state after a military coup overthrew Egypt's elected president, Mohamed Morsi, in 2013.
The Egyptian army said that the security operation was going on in a bid to ‘eradicate' the remaining militants in the area. The military did not reveal where exactly in northern Sinai the attack had taken place.
Thursday's attack was the deadliest since an assault on a checkpoint killed 12 soldiers and wounded six others in the Sinai peninsula. Daesh had claimed responsibility for that attack.