That quake's epicenter was about 42 miles from the city of Gangtok and 169 miles east of Kathmandu, according to the geological survey.

CNN: 18 dead in India, Nepal after magnitude-6.9 quake

At least four fighter jets were carrying rescue officers to a neighboring region, where they travel by road to Gangtok, Sikkim's capital, according to the alert.

CNN: 18 dead in India, Nepal after magnitude-6.9 quake