French prosecutors said on Thursday they had opened a terrorism investigation into a recent attack on park rangers in northern Benin, in which a French national was among six people killed.
Earlier in the day, France condemned the ambush in the park, which is jointly managed by Benin, Burkina Faso and Niger.
"The national anti-terrorist prosecutor's office has opened a probe with a charge of murder in connection with a terrorist undertaking after having been informed of the passing of a 50-year-old French national following a terrorist attack in the W park, north Benin", the prosecutors said in a statement.
Five rangers and a soldier were killed and 10 others were wounded when unknown militants raided the patrol in W National Park, the South African non-profit that manages the park, African Parks, said on Wednesday.
It was the deadliest in a string of attacks since December in northern Benin, where groups linked to al Qaeda and Islamic State have spilled over from Burkina Faso and Niger.
Recent attacks in Benin, Togo and Ivory Coast have highlighted the expansion of Islamist violence from the landlocked Sahelian countries, where an insurgency has raged for much of the last decade, to West African coastal nations.
Former French military members have trained park rangers and accompanied them on patrols in Benin, where African Parks manages the W and Pendjari National Parks.
(Reporting by Benoit Van Overstraeten; Editing by Chris Reese and Leslie Adler)