Only 80 Amur leopards exist in the wild, so these cubs are vital in the battle against extinction.
The pair are around four months old. Picture: Land of the Leopard
In recent years, the Siberian - or Amur - leopard almost died out: in 2007 there were as few as 30 in the wild.
Recent estimates suggest a figure of 80 of these big cats in the Russian Far East as they edge their way back.
These cubs, caught by a wildlife camera, are the first proof that leopardess Bary - aged 4 - has given birth in the Land of the Leopard National Park, set up by the Russian government to ensure the survival of the most threatened cat species on the planet.
The pair are around four months old and staff at the park have hailed the 'delightful news' which means a 2.5% increase in the Amur leopard population.
Staff at the park have hailed the 'delightful news' which means a 2.5% increase in the Amur leopard population. Pictures: Land of the Leopard
'When we found out who was in the shots we were incredibly delighted because it was the first trustworthy information about the family life of this female,' said research Viktor Storozhuk.
Bary is the daughter of legendary leopardess Kedrovka, and the pair featured in an internet film series Spotty Family in 2014.
'Now we know for sure, that the precious genes of Kedrovka are safe, the family tree is growing with new generations of leopards. iI am sure that this video is the beginning of the new adventurous story,' Victoria said.
Watch the world's rarest cat with two new cubs
The mother is seen hunting food for the leopards and teaching them the basics of hunting.
There are fears for Bary and her cubs as the cave where the leopardess and her cubs were found is known to have been on the route of a prowling Siberian tiger.
'This fact tells us that the life of this young mother is not idyll,' said a statement from the park. 'Bary looks calm in front of the trail camera but in reality she has to be in control of everything around and to be secretive.
'In order to protect her kittens, she must be careful and should not draw any extra attention, because her newborn predators have enough enemies in the wild.'
But they cubs have 'survived through early babyhood and it means they have every chance to grow up'.
The sex of the cubs is not know yet.
The father is believed to be male leopard Leo12M named Taifun who has been seen in Kedrovaya Pad nature reserve, part of Land of the Leopard National Park.
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