An Army helicopter with two pilots and two soldiers on board went missing during a routine training exercise over north Sikkim near the Chinese border on Thursday. The Army said it has launched a search,but bad weather is stalling the rescue operation. The Advance Light Helicopter Dhruv of the Army Aviation Corps took off from the Sewak Road Base in Siliguri in Bengal,from where the Army flies to Sikkims borders with China,at 10:30 am,said Army officials. The helicopter lost radio contact around 11.20 am. The chopper went down about 15,000 feet above ground near the Yumisamdong area which is now under a thick blanket of snow and covered with dense forest. The area is around 15 km above Lachung village in north Sikkim. The Army has launched a search operation but after about five hours,the search was postponed due to inclement weather, said an Army spokesperson. Sources ruled out the possibility that the chopper may have been shot down by the Chinese.