India, July 24 -- The bodies of all 25 workers killed after an under-construction tunnel collapsed in Sikkim's Namchi district, following an explosion of suspected methane gas, were recovered on Thursday, bringing to an end a nearly 96-hour search and rescue operation, officials aware of the matter said.

The workers were trapped inside Adit-3, a section of the 15-km-long tunnel of the National Hydroelectric Power Corporation Limited (NHPC) Teesta Stage VI Hydropower Project connecting the barrage at Sirwani with the powerhouse at Tarkhola in South Sikkim. The incident took place around 1 pm on Monday.

"The four-day search and rescue operation at the under-construction tunnel of the National Hydroelectric Power Corporation Limited (NHPC)...