YAOUNDE, Cameroon

Chairman of the African Union Commission, Moussa Faki Mahamat, on Tuesday expressed his outrage and concern at the recurrence of terrorist attacks targeting civilians in Niger.

At least 137 Nigerien civilians were killed on Sunday in an attack on several localities near the Malian border.

“Condemning the latest attacks on March 21 in the Tahoua region in Niger, which resulted in the death of 137 people, the President of the Commission offers his condolences to the families of the victims," according to a statement.

Mahamat also reiterated the “urgent need to strengthen the fight against terrorism in the Sahel to preserve human lives.”

Following the attack, the Niger government announced a three-day national mourning to pay tribute to the victims.

It is the second deadly attack on Nigerien civilians in a week. On March 15, unidentified gunmen attacked and killed at least 58 civilians returning from a weekly market in the Banibangou department, Tillaberi region, near the Malian border.

Niger, Burkina Faso, and Mali in the Sahel are at the epicenter of one of the world's fastest-growing displacement and protection crises.

The region hosts 851,000 refugees and nearly 2 million displaced people, according to the UN Refugee Agency.