Gunmen on Friday killed a ranger in the Virunga National Park, home to endangered mountain gorillas in eastern Democratic Republic of Congo where armed groups also roam.
The sanctuary issued a statement saying 31-year-old Bizimana Karabaranga Emery, a father of two, died in the Chanika area of North Kivu province.
"Our colleague was the victim of shooting" by unidentified attackers, the park said. "He died of his wounds."
The statement added that members of the Congolese armed forces (FARDC) were with the rangers when they came under fire.
The murder comes soon after trained guards returned to patrol a 144 square kilometre section of Virunga, at Chanika, at the start of the month.
The park covers 7,800 square kilometres (3,000 square miles) and runs up to the borders with Rwanda and Uganda.
It opened in 1925 and is Africa's oldest nature reserve, home to rare species, including the primates, which also inhabit the neighbouring states.
The haven has been the theatre of clashes between gunmen and park rangers, of whom 21 had died in the past year.
Dozens of armed groups roam eastern DRC, many of them a legacy of regional wars two decades ago, according to the Kivu Security Tracker (KST), a respected US-based monitor of violence in the region.
