Purported Boko Haram militants killed dozens of villagers Tuesday in an attack on the village of Njaba in Nigeria’s Borno state, according to various reports. Authorities did not learn of the assault until Thursday due to Njaba’s remote location.

The assailants attacked early Tuesday while many villagers attended morning prayer services at a mosque, witnesses told news website Sahara Reporters. It’s unclear how many villagers were killed in the attack, but witnesses placed the figure at anywhere from at least 45 to as many as 64 dead, according to reports by Reuters and the BBC. Many of the dead reportedly fell in and around the mosque; some were found with their throats slit. The militants also set fire to the village.

“I ran into the bus. Since then I [have] never seen my husband and three children,” Njaba villager Fatima Abaka said. “[I] came back to our village in the afternoon. Dead bodies were scattered everywhere.”

Njaba is located about 60 miles south of Maiduguri, the capital of Borno state and a hotly contested location in the ongoing war between Boko Haram and regional coalition forces composed of soldiers from Nigeria, Chad, Cameroon and Niger. The Nigerian army repelled Boko Haram attacks on a pair of villages Thursday.

News of the Njaba attack came one day after Chadian President Idriss Deby warned Abubakar Shekau, Boko Haram’s leader, to surrender to coalition forces or face death, according to Reuters. Coalition soldiers have killed hundreds of militants and recaptured several towns in recent weeks as part of a push to regain territory in northeast Nigeria. Boko Haram militants have responded with cross-border raids into Chad, Niger and Cameroon.

“Abubakar Shekau must surrender. We know where he is. If he doesn’t give himself up he will suffer the same fate as his compatriots,” Deby said. “He was in Dikwa two days ago. He managed to get away but we know where he is. It’s in his interests to surrender,” he said.

The African Union voted in January to approve the regional coalition force. The office of Nigerian President Goodluck Jonathan assured citizens affected by Boko Haram’s attacks and suicide bombings that coalition forces had gained an advantage on the Islamist faction.

“The president assures all Nigerians and the people of the northeastern states in particular that the days of mourning victims of incessant terrorist attacks in the country will soon be over as the tide has now definitely turned against Boko Haram,” Jonathan’s office said in a statement, according to the BBC.