YANGON - A food supplying Thai helicopter supporting the search and rescue operation of two missing Myanmar mountaineers went missing Saturday afternoon, sources with the Htoo Foundation said early Sunday.

The helicopter, Advance Aviation B-4, on its way to the base camp for supplying food, lost contact with the ground 20 minutes after it took off from Putao airport on Saturday afternoon at 2:20 p.m. (local time).

Aboard the helicopter were Thai pilot Chat Chawali, Myanmar pilot U Aung Myat Toe and personal secretary of U Tay Za, patron of the Htoo Foundation, which is a local rescue team, the sources said.

Search and rescue operation for the two missing is continuing in full swing.

Rescue teams from China, Nepal, Thailand and the United States, joining the local teams, also participated in the search and rescue operation.

The two Myanmar mountaineers, expedition leader Aung Myint Myat and manager Wai Yan Min Thu, went missing on Mount Hkaka Borazi along China-Myanmar border and have lost contact with the rest of their team since Aug. 31.

A total of eight Myanmar climbers from a hiking and mountaineering association, set out for an ascent trip on July 31. The two went missing on their descent trip after reaching the summit at about 4:25 p.m. (local time) on Aug. 31.

The remaining six descended from the base camp to Ta-phun-tan village at 8 p.m. (local time) on Sept. 9.

Mount Hkaka Borazi is located in the eastern Himalayas at the point where the country connects India and China. A geological survey carried out in 1925 measured the peak of the mountain at 5, 881 meters above sea level.