Gangtok: At least 12 labourers were killed when a dam being constructed by a private firm collapsed near Rongli in East Sikkim district, police said on Friday.

The Rang Po dam collapsed at about 9.00pm last night and so far 10 bodies have been recovered, but the toll could mount as it was still not clear how many labourers were at work at the site, Superintendent of Police M S Tuli said.