India, July 21 -- At least 27 people were trapped inside an under-construction tunnel of the Teesta hydroelectric project in Sikkim on Monday when the site was hit by landslides, officials said, adding that initially 43 workers were inside the tunnel, but 16 of them managed to come out safely.

The incident took place around 3.40 pm at Samardung in Namchi district.

"Nothing certain is known about the condition of the workers trapped inside. Three back-to-back rescue attempts have failed," Anupa Tamling, the district collector, said.

According to Sikkim government officials, the tunnel is a part of the National Hydroelectric Power Corporation's (NHPC) Teesta Stage VI hydroelectric power project. Tamling said according to reports received...