NIAMEY, Niger (AP) — Unidentified gunmen killed six French citizens and two Nigerien guides who were visiting a wildlife park east of Niger’s capital early Sunday, the West African nation’s interior ministry said.

French President Emmanuel Macron's office confirmed that some French citizens were killed during the attack but would not elaborate. Macron had a phone call with Niger President Mahamadou Issoufou on Sunday evening, his office said.

The attack took place in Koure, where Niger has a giraffe reserve, Oumarou Moussa, the adviser to Niger's interior minister, told The Associated Press. The area is a protected national park that contains dense vegetation and tall trees about 70 kilometers (45 miles) southeast of the capital. Hundreds of people visit each year to see its distinctive giraffes.

The park is in the Tillaberi region, where jihadists linked to Islamic State killed four U.S. soldiers and five Nigeriens in 2017.

The French government has warned citizens against traveling outside of the capital of Niamey as militants linked to Boko Haram, Islamic State and al-Qaida still carry out attacks across the vast West African nation. Niger borders several countries including Mali, Burkina Faso, Chad, Nigeria and Libya.

Violence by groups linked to IS and al-Qaida is on the rise in the Sahel region. France has deployed thousands of soldiers to help fight the growing insurgency there, and a local Sahel force made up of soldiers from Mali, Niger, Burkina Faso, Chad and Mauritania has also been fighting the extremists.