District Magistrate Anurag Srivastava said the landslide occurred early in the morning and was triggered by expansion work on NH 10 near Bengal-Sikkim border at Bhotebhir.
As large boulders came rolling down it hit a truck and killed its driver. Later two children were rescued from the debris.
Two tourists were also rescued from a car which was covered by the boulders, the DM said.
Some boulders even rolled down to Teesta river.