DAKAR, Senegal (AP) — Niger will hold three days of national mourning after an attack on two villages in the nation’s southwest that killed more than 100 civilians, the government said.

The government is strengthening security in the area of the attacks near the border with Mali and will provide support to those living there, it said in a statement after an emergency Cabinet meeting called by President Mahamadou Issoufou late Monday.

The attacks on the western villages of Tchombangou and Zaroumdareye took place on Saturday, the same day that Niger announced its presidential elections would go to a second round to be held on Feb. 21.

The villages in the insecure Tillaberi region were attacked after residents killed two rebel fighters, local officials said. Niger’s Prime Minister Brigi Rafini visited the two villages Sunday.

The attacks are among the deadliest in Niger and come on the heels of several others, including one by the Islamic State West Africa Province in the Diffa region a few weeks ago in which dozens of people were killed.

Niger and neighboring Burkina Faso and Mali are battling the spread of deadly extremist violence which is displacing large numbers of people, despite the presence of thousands of regional and international troops.

While no group has claimed responsibility for Saturday’s killings, the Islamic State in the Greater Sahara has been mounting attacks there for some time.

Niger is pressed on all sides by extremist groups and must deal with instability spilling over from both Mali and Nigeria, which is exacerbated by local tensions.