Two new cubs from one of the world's rarest big cats have been born at Twycross Zoo in Leicestershire. The Amur Leopard cubs are a boon to the zoo's conservation effort of a species that is thought to have less than 70 individuals left in the wild.

Aside from the around 70 in the wild, a further 200 live in zoos around the world. The World Wildlife Fund describes them as "probably the rarest and most endangered big cat in the world." The few surviving wild leopards are found in the border region between far eastern Russian and north east China.

The IUCN classifies the Amur leopard (panthera pardus orientalis) as critically endangered. Habitat destruction and poaching are the main factors still threatening the cat's future.

The new cubs have yet to leave their den but the zoo has set up a live stream people can watch from outside. The parents of the cubs were described to the BBC as a "real asset" in the Amur leopard breeding programme as they also produced two cubs in 2014.

"We are excited about our new arrivals and it is great to see how their mother is confidently responding to the cubs now that she is a more experienced mum," said Dr Charlotte Macdonald, Director of Life Sciences, "The birth is fantastic news for the entire species as Twycross Zoo actively participates in the conservation of the critically endangered Amur leopards and captive-bred cubs such as these two could help ensure the long-term survival of the species."

The zoo is hoping that they will one day be able to release the cubs as part of a breeding programme for the endangered cat.