Updated

The Nigerian government is finally turning the tide on Boko Haram, the ISIS-aligned terrorist group that has held the north in its bloody grip for years, a prominent Christian bishop from the embattled region told FoxNews.com.

“In the last six months, there has been significant progress," Bishop Matthew Hassan Kukah of the Catholic Diocese of Sokoto State told FoxNews.com during a recent visit to New York. "We can proudly say, they no longer control territory and that they are literally on their last legs now.”

Kukah said the central African nation’s recent advances against the extremist group have been hard-won. The terror group has existed for more than a decade, but gained international infamy in April, 2014, when members kidnapped 276 Christian schoolgirls from the town of Chibok, in the northern Borno state.

Some 57 of the girls escaped and others are feared dead. But the terrorist group is believed to be holding as many as 200 more than two years after seizing them. The government in Abuja has sought their safe return even as it has waged war on the Islamist terror group.

"Boko Haram has become outed and they are no longer a threat to the Nigerian society," he said. "[They] are now involved in some sort of back door negotiations with the federal government, and these negotiations are certainly tied to the release of the Chibok Girls.”

kukah1

Bishop Kukah was in the US late last month under an invitation from the Aid for the Church in Need, and recently gave a speech at the Cardinal Egan Catholic Center of New York University. (NICHOLLSPHOTOGRAPHY.COM)

Last month, Nigeria's government said it was examining a "proof of life" video showing 15 of the schoolgirls, the first footage of the missing girls released since May, 2014, when Boko Haram put out a video showing about 100 of them in Islamic garb and reciting the Koran.

“What we saw on the video recordings a week or so ago is a source of hope," Kukah said. "The girls look healthy. They didn’t look physically harmed in anyway, but, of course, one should not be carried away...These are only pictures. We don’t know what the real story is.”

Kukah said international aid has helped the Nigerian government gain the advantage in the fight against Boko Haram, which is based near the border with Chad, and believed to be largely holed up in a giant forest.

As recently as Friday, the U.S. administration is currently seeking to approve the sale of about 12 light attack aircraft to Nigeria to help in their battle against the terrorist group according to Reuters.

Kukah was in the U.S. last month by invitation from the Aid for the Church in Need. While here, he gave a speech at the Cardinal Egan Catholic Center of New York University and highlighted the conflict between Christians and militant Muslims in his homeland, which he traced back hundreds of years.

kukah2

Kukah says that while advancements have been made in the fight against Boko Haram, Christians still face problems in the northern parts of the country. (NICHOLLSPHOTOGRAPHY.COM)

“In northern Nigeria, Islam as we know it today arrived with the sword and blood, then slavery, subjugation and oppression," he said.

The conflict continues today, with suicide bombings, kidnappings, murder and anti-Christian propaganda aimed at youth.

"Young Muslims have been fed on a steady diet of exhortations that Islam is superior to any other religion," he said.