Cameroonian security forces are combing the area where Gilberte Bussières — a nun from Quebec — was abducted by gunmen overnight Friday, according to officials.

"We have been everywhere. Since the abduction, we have been on the ground,” said the governor of the region, Awa Fonka Augustine, told Agence-France Presse (AFP).

Authorities say they do not know if the people who kidnapped Bussières and two Italian priests are still in Cameroon or have crossed the Nigerian border.

“All [the north] of the country was secured shortly after the kidnapping,” said Cameroon's Minister of Defence Edgar Alain Mebe Ngo'o.

Health worries 

The nun, 74-year-old Gilberte Bussières, is from Asbestos, Que. and belongs to the Montreal-based Congrégation de Notre-Dame. According to the congregation, Bussières has worked in Africa since 1979 and ran a school in Douvangar, Cameroon.

A childhood friend, Bernadette Blais-Fréchette, says she is worried she may never see Bussière again.

She says Bussière had cancer treatment in Canada two years ago and is still weak.

"She convinced her doctor to let her go back because was worried about the people she left behind in Cameroon," said Blais-Fréchette.

The two priests, Giampaolo Marta and Gianantonio Allegri, came from the Diocese of Vicenza in northern Italy .

No claim of responsibility

No one has claimed responsibility for the kidnappings, but the Cameroonian security forces say they believe it was orchestrated by the Boko Haram, a militant Islamist group based in Nigeria.

In 2013, the group abducted a French priest, Georges Vandenbeusch and, later in the year, the Moulin-Fournier family. Everyone was later released unharmed.

Father Henri Djonyang, vicar of the parish in Maroua-Mokolo in Cameroon, said he has not heard from the three victims since they were taken.

"We will hold a mass to comfort people. Everything is in God's hands. We pray and hope they will be released,” Djonyang told AFP.

With files from Radio-Canada