Algeria's army on Friday killed four armed Islamists in the northern province of Ain Defla who allegedly belonged to a group that carried out a deadly attack last year, the defence ministry said.

It said they were part of "a bloody terrorist organisation which attacked our forces in the same region on July 17, 2015", killing nine soldiers.

Al-Qaeda in the Islamic Maghreb (AQIM) claimed responsibility for that attack.

The ministry said the four Islamists were killed during an army patrol in the Awlad Hamida area of Ain Defla and that automatic weapons and grenades were seized.

A total of "157 terrorists, including 10 commanders" were killed or arrested in such operations last year, according to the defence ministry.