A spokesman for a coalition of separatist groups in Mali says members have attacked a town in central Mali, moving violence further south after a cease-fire was broken last week.

Moussa Ag Attaher of the Coordination of Azawad Movements said Tuesday that they attacked the town of Tenenkou in the central Mopti region. He said the violence was a reaction to the attack against the town of Menaka last week by groups allied with the government, which broke a cease-fire agreement.

Violence has continued in northern Mali since. Experts worry it will upset a peace accord meant to be signed May 15 between various armed groups, separatists and the government.

Radhia Achouri, a spokeswoman for the U.N. mission in Mali, confirmed the attack, emphasizing the need to respect the cease-fire.