KUNMING, July 18 (Xinhua) -- A group of at least 320 rare Phayre's leaf monkeys have been sighted in southwest China's Yunnan Province, a local zoology institute said.

The monkeys were seen and photographed by researchers from Kunming Institute of Zoology under the Chinese Academy of Sciences during a three-month field investigation in Dehong Dai and Jingpo Autonomous Prefecture.

It is the largest group of the species ever recorded in a single region in China, said Jiang Xuelong from the institute.

Many of the female monkeys were holding newborns, showing that the group is healthy and able to reproduce, Jiang said.

The species, which lives primarily in areas of western Yunnan and eastern and northern Myanmar, is one of China's most endangered wild animals under national protection. It is also listed as endangered on the International Union for Conservation of Nature (IUCN) Red List.

Files compiled in the 1980s show no more than 2,000 Phayre's leaf monkeys lived in Yunnan. Massive deforestation by the end of the 20th century further destroyed their habitat and reduced their population, said Chen Jianwei, with Beijing Forestry University.

A nature reserve will be established to further protect the monkeys, according to local authorities.