Landslides on NH 31A at Tenth Mile Tarkhola in West Bengal has cut off Sikkim from the rest of the country.Officials said today that the landslide occurred at 11 PM last night between Rangpo on Sikkim border and Melli in West Bengal.Border Road Organisation is trying to clear the debris.It has said that one-way traffic on the highway will be opened by the evening. The landslide followed heavy rains in north Bengal and Sikkim last week.