Nigerian and Cameroonian troops killed 22 suspected Boko Haram fighters and arrested three purported commanders of the Islamic militant group during a massive raid Monday along the mountainous border region that separates the neighboring countries. The combined forces also rescued 1,275 captives held in several terrorist hideouts, Nigerian army representative Col. Sani Usman said in an online statement Tuesday.

“During the operation, the troops cleared Nbaga, Bula, Dabube, Ybiri, Greya and Suduwa towns and other adjoining settlements. The towns and settlements were occupied by suspected fleeing Boko Haram terrorists who escaped from villages previously cleared by troops of the Nigerian army,” Usman said. “It is gratifying to note that the operation was a huge success as there was no casualty or injury on the troops.”

The suspected Boko Haram emirs arrested Monday were identified as Lawal Abba, Mallam Gana and Mallam Hisna from the towns of Shatte, Bula Burra and Bulla Jaja, respectively. The hundreds of captives who were freed are being registered and screened before being relocated to an internally displaced persons camp, Usman said.

The Nigerian military conducted the vast operation in conjunction with Cameroonian troops under the umbrella of the Multinational Joint Task Force, whose mandate is to crush Boko Haram’s brutal insurgency. Nigerian President Muhammadu Buhari last July appointed Maj. Gen. Iliya Abbah as commander of the 8,700-strong joint task force, which encompasses troops provided by Benin, Cameroon, Chad, Niger and Nigeria. The task force has its headquarters in the Chadian capital of N’Djamena.

Buhari has made battling Boko Haram a top priority of his administration. Since taking office last May, he has resupplied soldiers, replaced the Nigerian military’s top brass and moved its command center for the fight from the West African country’s distant capital, Abuja, to the heart of the militant group’s insurgency in Maiduguri in Borno state.

The Nigerian army said last week its troops have rescued thousands of civilian hostages during raids on Boko Haram’s territory in the border regions between Nigeria, Niger, Chad and Cameroon since Feb. 26. It also claimed 800 of the militant group’s fighters had surrendered in recent weeks.

The Nigerian military has made repeated claims of recapturing territory, winning skirmishes against Boko Haram and recovering weapons and equipment. Previous statements said dozens of the militant group’s members, including women and children, had surrendered this year and that many appeared emaciated and begged for food. But Boko Haram has continued to devastate local communities with hit-and-run tactics and suicide bombings, raising doubts about the Nigerian military’s claims that the militant group is losing the war.