New Delhi (CNN) -- At least eight people were killed and thousands displaced after powerful Cyclone Nilam roared into India's southeastern coast, authorities said Thursday.
About 8,000 people in low-lying areas on the coast of Tamil Nadu state were moved to temporary shelters, said Jatindranath Swain, the province's disaster management commissioner.
An oil tanker with 37 people on board got into difficulty as the storm made landfall Wednesday, he said. The high winds and strong waves set the vessel adrift and drove it toward the coast, where it ran aground, Swain said.
Naval divers engaged in rescue efforts at the stranded ship, according to Swain, but six crew members remained missing Thursday.
The India Meteorological Department said that Nilam crossed the southern coast at 4:30 p.m. Wednesday. It then moved inland and weakened into a deep depression, the agency said.
Emergency crews were patrolling vulnerable zones in Tamil Nadu, Swain said.
Governments in neighboring Andhra Pradesh state and the federally-administered territory of Puducherry had said they were prepared to deal with Nilam.
The national weather department was forecasting heavy rains in parts of Tamil Nadu, Andhra Pradesh and Puducherry.
"Gale wind-speed reaching 80-90 kph (50-56 mph) gusting to 100 kph (62 mph) would prevail along and off north Tamil Nadu, Puducherry and adjoining south Andhra Pradesh coasts during next 24 hours," it said Wednesday.
Weather officials also predicted a storm surge that was likely to inundate low-lying areas, mainly along Tamil Nadu's coast.
Forecasters warned that residents should expect extensive damage to thatched roofs and huts, advising fishermen not to venture into the sea until the storm has passed.