In a rare occurrence in the eastern Democratic Republic of Congo, twin mountain gorillas were recently born in the Virunga National Park, renowned for its biodiversity but threatened by conflict.

"The twins, believed to be a female and a male, are approximately two weeks old and are being closely monitored by field teams," the park authorities said Tuesday in a statement.

A similar event was reported in January in the park with the birth of male twins.

Despite the recent events, twin births among gorillas, and particularly the threatened mountain gorilla species, are considered highly unusual by experts.

"The arrival of twins among gorillas is a special occasion given their rarity," Tara Stoinski, CEO and chief scientific officer of the Dian Fossey Gorilla Fund, told AFP.

"From our nearly 60-year mountain gorilla database... we know that they occur in less than one percent of births."

The survival of gorilla twins poses a challenge because "not only must the mother carry two infants, which makes walking more difficult particularly in the first few weeks... they must produce more milk, which is energetically very expensive," Stoinski explained.

Virunga National Park is the oldest nature reserve in Africa, inaugurated in 1925, and is listed as a UNESCO World Heritage Site.

But intensified conflict in the eastern DRC, where the M23 armed group has seized swathes of territory in recent years, poses threats to the site.

Virunga's forests are also believed to have been used as a hideout by fighters from the ADF, a terrorist organisation.

Globally, the mountain gorilla population is estimated at 1,063 living in the wild, with some 350 gorillas recorded in Virunga in 2021, according to park authorities.