Yaoundé, Cameroon—

Troops in Chad and Cameroon have rescued dozens of civilians kidnapped for ransom or fighting jihadist groups on both sides of the Central African country’s border.

Military officials from both countries say the number of civilian kidnappings has increased along the border, with hundreds still being held.

Cameroon’s military said on Tuesday it had received five civilians from Chadian government forces, including a 54-year-old man and four others aged between 17 and 24.

The five men, who were abducted this year from villages around the Chadian border towns of Koussery and Logone Birni, were escorted to the governor’s office of Cameroon’s Far North region on Wednesday, Cameroonian government officials said.

Victor Boukar, one of the former hostages, said heavily armed men chained their legs every night and tied their hands with ropes during the day. He said they were frequently tortured during their 70 days in captivity and were given only one meal a day.

Boukar said the kidnappers often forced the 35 captives, including seven women, to move to different locations on both sides of the border between Cameroon and Chad to avoid attempts by government forces to rescue them.

Hostages whose families paid ransoms were abandoned in the jungle, he said, adding that armed men had representatives collecting ransoms in border towns and villages.

Chad said last week that its forces had launched attacks on border villages in Mayo-kebbi East and Mayo-Keb West provinces, where hundreds of people were being held hostage by armed groups and jihadists. Soldiers allegedly freed dozens of civilians. The Cameroonian national has returned to his home country and the Chadian national has been reunited with his family after receiving medical care.

Midjiyawa Bakari, the governor of the Far North region, said Chad and Cameroon were reuniting to fight insurgents and achieve peace along their more than 1,100 kilometers (680 miles) of land border.

He said Cameroonian border guards would arrest or kill armed men and jihadists hiding in local towns and villages, and Cameroon allowed Chadian troops to cross the border in hot pursuit of Boko Haram militants and armed groups.

Gen. Ahmet Kogli, a military adviser to Chad’s transitional president Mohamed Idriss Deby, told Chadian state television on Wednesday that Boko Haram militants were seeking to to obtain supplies to resume attacks and kidnappings.

Kogeri said troops fighting to restore peace had noticed Boko Haram and its splinter jihadist group once again attacking people and seizing goods. He said civilians should report all strangers in border towns and villages to government forces.

Boko Haram attacks began in Nigeria’s Borno state in 2009 and spread to Cameroon, Chad and Niger.

The United Nations says the Islamist insurgency has killed more than 37,000 people, mostly in Nigeria, and displaced more than 3 million people.