The Switzerland-based World Wildlife Fund has reached an agreement with a London-based oil company that could prevent drilling in a park that is home to about a quarter of the world’s remaining mountain gorillas, HuffingtonPost reports.

The Congolese government authorized London-based SOCO International to explore for oil in Congo’s Virunga National Park by after oil was discovered there in 2010. Based in Gland, Switzerland, World Wildlife Fund said the decision was illegal.

Virunga is a UNESCO World Heritage site.

In a joint statement Wednesday, WWF and SOCO agreed there will be no exploratory drilling in Virunga unless the government and UNESCO agree it would not threaten the park’s world heritage status.

SOCO agreed to stop exploring for oil after completing seismic testing on Lake Edward and WWF said it would drop a complaint that the oil company violates good-practice business
guidelines set out by the Organization for Economic Cooperation and Development.

SOCO denied it had withheld information about the environmental risks of drilling on land that overlaps with the park.

The Eastern Congo park is also the only place where all three African great apes can be seen. The struggle over Virunga’s resources has led to violence, HuffingtonPost reports. In April, Chief Warden Emmanuel de Merode was attacked by three gunmen while driving through the park.

Soon after that attack, British filmmaker Orlando von Einsiedel released “Virunga,” a documentary that depicted the desperate struggle by de Merode and the park rangers to protect the park and its wildlife from the oil company, rebels and armed militias.