Yaounde/Paris: Military helicopters are searching for a vacationing French family of seven kidnapped in Cameroon and security around the region is being increased amid tensions over France’s role in western Africa.

Cameroonian President Paul Biya ordered tight security measures and urgent steps to free the hostages, who include four children. They were kidnapped by armed gunmen in the country’s far north on Tuesday and whisked across the nearby border to Nigeria. A ministry statement said the Cameroonian government is in contact with Nigerian and French authorities.

Officials suggested the involvement of Boko Haram, one of Nigeria’s extremist groups.

France’s defence minister said Wednesday that there was no proven link between the French operation in Mali and the Cameroon kidnapping. But, speaking on France-2 television, Jean-Yves Le Drian said: “These are groups who adhere to the same fundamentalism and who have the same methods, whether it is in Mali, in Somalia or in Nigeria, who want to create a lawless zone” stretching from the Atlantic across the southern edge of the Sahara to Sudan.

France on Wednesday urged its citizens to leave northern Cameroon after the kidnapping issue.

The French foreign ministry in a notice urged citizens in the far north “to leave the area as quickly as possible” and advised against travel to areas bordering Nigeria until further notice.

The ministry could not say how many French citizens are believed to be in the north but 6,200 in total are registered as living in Cameroon. A Cameroonian government official said military helicopters were being used in the search.

The French gas group GDF Suez identified the captives as an employee working in the Cameroon capital of Yaounde and his family. French media says the children are between five and 12 years old.

Cameroon state television cited government sources in the locality saying that the three adults have been separated from the four children.

The family was on tour at the Waza National Park in Cameroon’s Far-North Region before they were abducted at gunpoint by five gunmen on board motorbikes, according to paramilitary sources in the area.

A Cameroon government statement late Tuesday night said the hostages were abducted at Sabongari, 7km from Dabanga, which flanks Cameroon’s frontier with Nigeria. The statement did not say whether the Cameroon government is in contact with the kidnappers.