More than 1,000 rescue workers and soldiers have begun clearing away piles of uprooted trees and electric poles blocking roads after a powerful cyclone slammed into India's eastern seaboard, leaving at least eight dead.

Rescuers were readying dozens of helicopters, aircraft, ships and boats to carry out relief operations once they get a clearer idea of the extent of damage in Andhra Pradesh and Orissa states, said Anil Shekhawat, an Indian official.

Weather forecasters downgraded Cyclone Hudhud to a tropical depression as it moved further inland on a course north-northwest of the city of Visakhapatnam, where it made landfall Sunday.