A pair of twin mountain gorillas has been born in the eastern Democratic Republic of Congo - a rare occurrence for the endangered primates, conservationists at Virunga National Park say.

The community trackers, who discovered 22-year-old Mafuko hugging her newborns on Saturday, said the mother and her two baby sons all appeared to be well and healthy.

Twin births are thought to account for about 1% of all mountain gorilla births, though exact data is not widely available.

Virunga, situated in a conflict-prone part of DR Congo, is Africa's oldest and largest national park and was set up 100 years ago to protect mountain gorillas of which there are fewer than 1,100 left in the wild.

They are only found in the Virunga and in national parks over the border in Rwanda and Uganda, according to the International Union for the Conservation of Nature (IUCN), which compiles a Red List of threatened species.

The last birth of mountain gorilla twins in Virunga National Park was in September 2020.

Mafuko herself gave birth to twins in 2016, but they both died within a week.

Young gorillas rely entirely on their mothers for care and transport - and are extremely vulnerable in what can be a dangerous environment where poachers and many armed groups operate.

The authorities at the park say additional monitoring and protection measures have been put in place to ensure the twins' survival during this critical period.

Rangers would closely observe the young family and provide support if needed, they said.

A gorilla's pregnancy lasts for about eight-and-a-half months, and females usually give birth to one infant every four years.

According to Virunga conservationists, Mafuko has had a remarkable history of survival herself.

Born in 2003 into the Kabirizi family, she lost her mother to armed attackers when she was four years old.

She joined the Bageni family when she was 10 - and to date has been pregnant and given birth five times.

Conservationists at Virunga, which is a Unesco World Heritage Site, say her latest offspring represent a significant boost for efforts to protect the endangered species.

Thanks to anti-poaching patrols and community programmes - supported by the European Union and Unesco - mountain gorilla numbers in Virunga have slowly increased over the past decade.

This success, which is documented by the IUCN and other partners, led to their status being upgraded from "critically endangered" to "endangered" in 2018.

Virunga spans 7,800 sq km (3,000 sq miles) and is home to an astonishingly diverse landscape - from active volcanoes and vast lakes to rainforest and mountains.