Kano, Nigeria (CNN) Hundreds of troops from Chad and Niger launched a ground and aerial offensive against Boko Haram in northeastern Nigeria on Sunday, according to residents and military sources from Niger.

The sweeping offensive is taking place along the Niger-Nigeria border, sources said, effectively opening a new front in the fight against the Islamist terror group.

This comes a day after Boko Haram pledged allegiance to ISIS in an audio message purported to be from leader Abubakar Shekau.

"Early this morning, troops from Niger and Chad launched ground and air raids against Boko Haram into Nigeria, and the operation is still continuing," said a military official in the border town of Diffa, Niger.

"It is an intensive operation that is aimed at pulverizing Boko Haram and crippling their capability," according to the source. He spoke on condition of anonymity because he is not authorized to comment publicly about the operation.

‎Residents said artillery fire and fighter jets pushed Boko Haram fighters into the Damasak district of Nigeria, which is a Boko Haram enclave.

"Around 6 a.m., soldiers from Niger and Chad in huge numbers confronted Boko Haram around the Doutchi area outside Diffa and later crossed the bridge into Nigeria," said Diffa resident Ari Boubakarna.

Photos: West combats Boko Haram, ISIS in Africa's deserts Photos: West combats Boko Haram, ISIS in Africa's deserts A U.S. Special Forces operator looks on as a Chadian Special Forces soldier takes aim. Exercise Flintlock focused on small arms tactical training in Mao on February 22, 2015. Hide Caption 1 of 7 Photos: West combats Boko Haram, ISIS in Africa's deserts Nigerian Navy Special Forces run through drills under the training of British Special Forces. Hide Caption 2 of 7 Photos: West combats Boko Haram, ISIS in Africa's deserts A U.S. Special Forces Operator walks toward a recently landed C130 cargo plane. In just a few short weeks, this barren stretch of Sahel was turned into a functioning military outpost. Hide Caption 3 of 7 Photos: West combats Boko Haram, ISIS in Africa's deserts A man looks on as a U.S. Air Force C130 touches down. Hide Caption 4 of 7 Photos: West combats Boko Haram, ISIS in Africa's deserts Members of the Nigerian Navy's Special Boat Services Unit cook a meal over an open fire. By day, temperatures in Mao rose to approximately 35 degrees celsius (95 degrees fahrenheit), making evenings the only time to relax. Hide Caption 5 of 7 Photos: West combats Boko Haram, ISIS in Africa's deserts CNN photographer Brice Laine works under a mosquito net in a makeshift edit suite during Exercise Flintlock. Hide Caption 6 of 7 Photos: West combats Boko Haram, ISIS in Africa's deserts CNN correspondent Arwa Damon interviews Chadian Captain Zakaria Madaga at his unit's camp. "If you have this kind of training you can defend yourself from death," says Madaga. Hide Caption 7 of 7

"We heard huge explosions from artillery fire and fighter jets, but the explosions receded ‎as the troops moved further into Nigeria," Boubakarna continued.

A journalist working in Diffa saw ‎troops headed toward the border with Nigeria, where Boko Haram fighters had taken up positions.

‎"They left in a huge convoy of over 200 vehicles, some of them fitted with machine guns, including armored tanks, ambulances, water tankers and cargo trucks, which indicate they were going for a prolonged operation," the journalist said.

‎Residents lined up the streets to offer water and tea as the troops drove out of Diffa, residents said, adding that soldiers promised to capture Shekau alive.‎

‎Another contingent of troops, backed by air support, moved out from the town of Bosso, Niger, according to residents.

"Soldiers in large numbers crossed into Nigeria this morning, and we could hear thunderous sounds of gunfire and explosions coming from the direction of Malam Fatori," Bosso resident Tandja Moumouni said.

Nigeria and its neighbors have recently mounted a coordinated offensive against Boko Haram militants in the Borno state, where the Islamist group has seized a large swathe of territory. Nigeria shares a border with Niger, Chad and Cameroon there.

Photos: Fighting Boko Haram in Cameroon Photos: Fighting Boko Haram in Cameroon Cameroonian forces are seen in Mabass, a village in northern Cameroon that overlooks a Boko Haram base in Madagali, Nigeria. Boko Haram militants attacked Mabass and the village of Makxy on January 18. Boko Haram is an Islamist militant group that has been waging a campaign of terror aimed at instituting its extreme version of Sharia law. Much of its violence has taken place in Nigeria. But neighboring countries, such as Cameroon and Chad, have also been affected. Hide Caption 1 of 8 Photos: Fighting Boko Haram in Cameroon Burned-out cars line the streets of Fotokol, Cameroon. Hide Caption 2 of 8 Photos: Fighting Boko Haram in Cameroon A Cameroonian soldier points his gun across the El Beid Bridge into Gambaru, Nigeria. Gambaru is considered one of the strongholds of Boko Haram. Hide Caption 3 of 8 Photos: Fighting Boko Haram in Cameroon Hide Caption 4 of 8 Photos: Fighting Boko Haram in Cameroon This picture shows a suspected Boko Haram insurgent who crossed the El Beid River in an attempt to infiltrate Cameroon. Hide Caption 5 of 8 Photos: Fighting Boko Haram in Cameroon This Boko Haram tank was destroyed by Chadian and Cameroonian troops. Hide Caption 6 of 8 Photos: Fighting Boko Haram in Cameroon Chadian troops head off to Gambaru on Thursday, February 12. Their truck is just about to cross the El Beid Bridge. Hide Caption 7 of 8 Photos: Fighting Boko Haram in Cameroon A Nigerian refugee holds her child at the Minawao Refugee Camp in northern Cameroon. She named her son Cameroon, a sort of tribute to the country that has given her a haven. Hide Caption 8 of 8

As a part of this alliance, thousands of troops from Niger and Chad were stationed in Bosso and Diffa in January.

‎The offensive has succeeded in reclaiming some of the territory seized by the group.

Nigeria has vowed to liberate all of its territories from Boko Haram before the general elections, which begin on March 28, to enable displaced residents return to their homes for the elections.