Yaounde, Cameroon (CNN) -- French military and intelligence officers have entered northern Cameroon in search of a family of seven French tourists kidnapped Tuesday from a national park, a CNN affiliate reported Wednesday.
The Paris-based private network BFMTV did not cite its source; it posted a team of journalists Wednesday in Paris at the French Foreign Ministry Crisis Center, which is handling the country's response to the crisis.
BFMTV, citing the French Defense Ministry, said gendarmes had been sent to the site in northern Cameroon where the abduction occurred to investigate.
But a Cameroonian official said Wednesday that he believed the family had been taken across the border into neighboring Nigeria within hours of their abduction.
Joseph Dion Ngute, the Foreign Ministry official in charge of ties with Commonwealth nations, said Tuesday's incident marked the first time foreigners in Cameroon had been taken captive by suspected Islamic militants of Nigeria's Boko Haram movement.
"The intentions of the kidnappers are yet to be known," he said.
French officials blamed the incident on Boko Haram, which has taken advantage of Nigeria's porous borders with Chad and Cameroon in its three-year campaign.
Boko Haram has waged a war against Nigeria's government and its Christian population in an effort to establish a strict Islamic state in northern Nigeria.
The family was kidnapped from Waza National Park, a thickly forested area of northern Cameroon popular among tourists and located near the border with Nigeria. The incident has raised fears of Westerners being targeted by Islamist militant groups in Africa in the wake of France's military intervention in Mali.
But French President Francois Hollande said Tuesday that he didn't believe the seizure was linked to his government's intervention in Mali, where French troops have joined government forces to battle Islamic militants linked to al Qaeda.
"I am aware of the presence of Boko Haram in that part of Cameroon, and that's worrying enough," Hollande said.
The abductees include four children ages 5 to 12, their parents and an uncle, the Cameroon's state broadcaster CRTV reported.
Fonkam Azu, governor Cameroon's northern region of Maroua, told reporters that residents saw the hostages being driven into Nigeria on motorcycles.
The father works for the French company GDF Suez and is based in Yaounde, the capital in southern Cameroon. GDF Suez, which is developing a natural gas liquefaction project in Cameroon, said it was working closely with the French Foreign Ministry.
Concerns about border security in northern Cameroon grew early last year, when Sudanese poachers on horseback invaded the Bouba Ndjida Park and killed more than 300 elephants for their ivory. Afterward, the government temporarily replaced park guards with a special anti-terrorist squad of the military.
In a statement, Cameroon's Ministry of External Relations said Wednesday that security has been tightened to guarantee the safety of expatriates and tourists, especially in volatile regions.
Abductions are common in Cameroon, especially in natural resource-rich regions.
In January, kidnappers killed one Chinese national and abducted three others from the Betare Oya gold mine in the country's south. The military freed the surviving hostages. And several abductions targeting foreigners have occurred in the oil-rich Bakassi Peninsula, on the country's Atlantic coast.