The remarkable pictures were taken by a 'photo trap' set by a one-time poacher who used to stalk the rare leopards. Picture: M. Markov, WWF Russia

These pictures were taken by a former poacher who has now defected to work for nature protection in the Altai Mountains in southern Siberia. The latest expedition to the Argut River valley - once the most populated region for snow leopards in Russia - brought some sensational results.

The expedition was organised by Altai regional 'Arkhar' organisation which works closely with Russian WWF on nature protection.

The remarkable pictures of the wild cubs romping on rocks were taken by a 'photo trap' set by a one-time poacher who used to stalk the rare leopards.

In March 2013 the unnamed man from a remote village - who for years was a professional hunter of snow leopards - was offered a deal that meant that he gave up poaching hunting and started working on protecting the animals.

The result is these pictures.

'The pictures we have received is proof that the gigantic amount of work invested in bringing the snow leopards back to Argut is bringing results. And what results!' Pictures of the snow leopard cubs and the river Argut valley: S. Spitsyn, M. Markov, WWF Russia

He agreed to trace and monitor the remaining snow leopards in some of Siberia's most inaccessible locations in return for a payment which is above the average made by snow leopard poachers. During the year he found evidence of a leopard family previously unknown to conservationists.

Sergey Spitsyn, from the Altai Nature Reserve, who was on the latest expedition to the mountains around Argut, said: 'The pictures we have received is proof that the gigantic amount of work invested in bringing the snow leopards back to Argut is bringing results. And what results! The snow leopards have begun to breed.'

The Argut population of the snow leopards was almost completely destroyed by poachers during what he called the 'mad 1990s'. This year's expedition proved that there are at least five or six snow leopards in the Argut area, raising hopes about restoring the population.

The snow leopard, slightly smaller than other big cats, is native to the mountains of Central Asia.

As few as 4,150 to 7,350 are believed to survive, with a much lower number reproducing, hence the international concern over their survival.

The latest expedition to the Argut River valley, once the most populated region for snow leopards in Russia. Picture: S. Spitsyn, WWF Russia

The snow leopards are found in Altai in small numbers but also in the Himalayas, the Pamirs, and the Tien Shan. A major threat to them is the surging global demand for cashmere, which is derived from the under hair of domestic goats and the livestock population of these animals has soared in recent years.

They consume the forage of mountain pastures that sustained a number of species of wild herbivores such as the ibex, the blue sheep, and the argali - the natural prey of snow leopards.

Here in Russia, the snow leopards are known for their exceptional and highly valued fur.

'Their bones and other body parts are in demand for use in traditional Asian medicine and wild snow leopards are sometimes captured for private animal collections in Central Asia,' states the Snow Leopard Trust. 'Many poachers are local residents who live in snow leopard habitat areas. These regions face high levels of poverty, and poaching offers a source of extra income that can be used to meet the most basic necessities of life, including food and shelter'.