* French president says four adults, three children taken
* Says kidnappers came into Cameroon from Nigeria
* Coincides with French forces pursuing rebels in Mali (Updates with Hollande, fresh details, background)
By Bate Felix and Jean-Baptiste Vey
DAKAR/ATHENS, Feb 19 (Reuters) - Gunmen kidnapped seven French nationals, including three children, on Tuesday in northern Cameroon near the border with Nigeria and the perpetrators came from neighbouring Nigeria, French President Francois Hollande said.
The risk of attacks on French nationals and interests in Africa has risen since France sent forces into Mali last month to help oust Islamist rebels occupying the country's north.
"They have been taken by a terrorist group that we know and that is in Nigeria," Hollande told reporters during a visit to Greece. Islamist militants in northern Nigeria now pose the biggest threat to stability in Africa's top oil-producing state.
Radio France International had earlier reported the kidnapping, saying that the seven people were taken by armed men on motorbikes and were being taken towards Nigeria.
Western governments have grown concerned that Nigeria's radical Islamists may link up with groups elsewhere in the region, particularly al Qaeda's North African wing AQIM given the conflict in nearby Mali.
The seven tourists were abducted at around 7 a.m. in a village about 10 km (six miles) from the Nigerian border near the Waza national park and Lake Chad in the extreme north of Cameroon where Westerners often go for holidays.
It was the first case of foreigners being seized in the mostly Muslim north of Cameroon, a former French colony.
"I see the hand of (Nigerian militants) Boko Haram in that part of Cameroon. France is in Mali, and it will continue until its mission is completed," Hollande said.
France intervened in Mali last month when Islamist rebels, after hijacking a rebellion by ethnic Tuareg MNLA separatists to seize control of the north in the confusion following a military coup, pushed south towards the capital Bamako.
Eight French citizens are already being held in West Africa's Sahel region by al Qaeda-affiliated groups.
Cameroon Information Minister Issa Tchiroma Bakary said he could not confirm the kidnapping report for now.
On Sunday, seven foreigners were snatched from the compound of Lebanese construction company Setraco in northern Nigeria's Bauchi state, and al Qaeda-linked Ansaru took responsibility.
Northern Nigeria is increasingly afflicted by attacks and kidnappings by Islamist militants. Ansaru, which rose to prominence only in recent months, has also claimed the abduction in December of a French national who is still missing.
An Ansaru statement said kidnappings were driven by "the transgression and atrocities done to the religion of Allah by the European countries in many places, such as Afghanistan and Mali." (Additional reporting by John Irish and Diadie Ba in Dakar, Vicky Buffery in Paris; Writing by John Irish; Editing by Mark Heinrich)