A new video released by Islamic militant group Boko Haram purportedly shows some of the missing Nigerian schoolgirls who were kidnapped last month.

In the video obtained by AFP news agency on Monday, a number of girls are seen in an undisclosed rural location, wearing full-length veils and reciting prayers in Arabic.

Boko Haram leader Abubakar Shekau said the girls won’t be freed until imprisoned Boko Haram fighters are released.

“I swear to almighty Allah you will not see them again until you release our people that you have captured," the leader says in the 17-minute video, as he cradles an assault rifle.

He also claims that the girls shown in the clip -- estimated to be about 130 -- have been converted to Islam.

“These girls, these girls you occupy yourselves with…we have indeed liberated them. These girls have become Muslims,” Shekau says.

Two girls are seen questioned by an unseen man in the clip. “Why have you become a Muslim?” he asks.

“The reason why I became a Muslim is because the path we are on is not the right path,” she answers. “We should enter the right path so that Allah will be happy with us."

The girl says she was converted from Christianity to Islam, and says her name has been changed to Halima.

Families of the abducted girls said most them are Christians.

A second girl is shown in the clip, saying the girls had experienced no harassment “except righteousness,” when asked if they had been ill-treated.

But the authenticity of the video hasn’t been verified, and Richard Downie, deputy director of the Center for Strategic and International Studies Africa program, said Nigerian authorities will have to ask parents of the missing girls to check the identities of the individuals in the video.

“We have to remember that Boko Haram has seized kidnapped girls and children before,” he told CTV News Channel.

“If the authenticity of the video is proved, the fact that these girls are still alive shows that he knows the value that they represent to him, and they do offer the prospect for a negotiation,” he said.

But Shehu Sani, a civil rights activist in northern Nigeria, said the Nigerian government rejected the prisoner swap, which he says is a “very big mistake.”

“The insurgents have nothing to lose, and we are talking about the lives of these girls,” he told CTV News Channel.

He added that the exchange of the Boko Haram prisoners for the kidnapped girls is the “only peaceful way we can get these girls alive.”

“Any attempt to use force to rescue these girls will turn out tragic and I fully support the idea of taking this opportunity to free them by a prisoner swap,” he said.

And while the video offers hope that some of the girls have not been sold, Downie says it’s likely that the abductees have been divided into smaller groups, which will make it harder for the government to find the girls.

“(Boko Haram) could also be operating in a very large area, either inside or outside Nigeria,” said Downie.

The group, deemed a terrorist organization by the U.S. in 2013, abducted nearly 300 girls on April 15 from a school in the northeast town of Chibok. Fifty-three girls managed to escape, but 276 remain in captivity.

In a video released last week, the group, whose name means “Western education is sinful,” claimed responsibility for the abduction, and threatened to sell the girls, who they described as “slaves”

Boko Haram has been waging a brutal campaign in Nigeria’s mainly Muslim northern states since 2009, fighting to overthrow the government and establish an Islamic state.

Following the mass abduction, Nigeria’s government was criticized of acting too slowly, and of refusing international help for weeks.

Meanwhile, Canadian troops arrived on the ground in Nigeria on Monday, to work with teams from the U.S. and the U.K.

France, China and Israel have also all offered to send specialist teams to find the missing girls.

Canada’s New Democratic Party also called for an emergency debate in Parliament scheduled for Monday, to consider a response to the mass kidnappings.

“This is the very definition of an emergency. Hundreds of young innocent lives are at stake, along with the political and social direction of a country and a region. Parliamentarians need an opportunity to discuss an appropriate Canadian response to this crisis,” NDP MP Paul Dewar said last week.

Meanwhile, concerned citizens around the world have been using social media to keep Boko Haram and missing girls in the spotlight, under the hashtag #BringBackOurGirls.

With files from The Associated Press