Five rangers and a soldier were killed and 10 others wounded in an ambush by unnamed militants in a northern Benin park on Tuesday, the park’s management said in a statement on Wednesday.

“In the afternoon of Tuesday Feb. 8, a team of rangers was ambushed in W National Park in Benin, while carrying out a patrol at the northern limit of the Park where it intersects with Burkina Faso and Niger,” African Parks said.

Tuesday’s attack was the deadliest in a series of recent incidents blamed on militants in the north of the country, increasing fears about widening Islamist violence.

African Parks, the South African non-profit group that manages the W National Park and the Pendjari National Park, said reinforcements from Benin’s army and additional rangers have been deployed on the ground.

Benin is among the West African coastal countries considered most vulnerable to a spillover of Islamist violence from the landlocked Sahel countries, where groups linked to al Qaeda and Islamic State exert influence over vast tracts of territory.

Two soldiers were killed and several others wounded in an attack in northern Benin in December. A Benin army vehicle struck an improvised explosive device in a national park near the border with Burkina Faso in January.

Benin’s government invited African Parks Network (APN) in May 2017 to take over management of Pendjari. The government coordinated with APN in September 2019 to implement a Priority Intervention Plan to urgently secure W National Park and a full management agreement for W was signed in June 2020.