LAGOS, Nigeria — Seven French tourists, including four children, were kidnapped in northern Cameroon on Tuesday, the second large-scale hostage-taking in the region in four days. The French president and foreign minister pointed the finger at Islamist terrorist groups operating across the border in northeast Nigeria, possibly including the deadly Boko Haram organization.

The kidnappings appeared to be part of the widening fallout from France’s military intervention against Islamist militants in northern Mali. Though French officials did not explicitly link the two in their statements on Tuesday, they invoked them together and vowed to continue the Mali campaign. All told, about 15 French citizens are now being held captive in West Africa.

The seven kidnapped on Tuesday are all members of the same family who live in Yaoundé, Cameroon’s capital. They camped on Monday night in Waza National Park in the far north of Cameroon and set out early Tuesday for the animal reserve of Kalamaloue, where they were going to view elephants, a Cameroon park official said. A security official said the group was seized near Dabanga, a frontier town, and was then taken across the Nigerian border into a region of semidesert and scrub where Boko Haram has its base.

Over the past four years, the region has faced dozens of assaults by the terrorist group, including bombings, ambushes and other attacks on civilians and security forces. Harsh counterterrorism tactics by the Nigerian security forces have only marginally damped the campaign.