India on Monday started evacuating thousands of people from fishing villages as Cyclone Vardah barrelled towards its southeastern coast at speeds of more than 100 kilometres (62 miles) per hour.
Heavy rains accompanied by high-velocity winds pounded the coastal districts of Tamil Nadu and Andhra Pradesh states, uprooting trees and disrupting power supply lines.
A high alert was issued in several affected districts, with eight fishermen having so far been rescued from the sea in view of the "very severe" cyclonic storm.
"We have already moved over 9,400 persons in seven vulnerable mandals (blocks) to safety. All necessary measures have been taken to ensure safety of people," P Narayana, a minister in the Andhra Pradesh state government, told the Press Trust of India news agency.
Another 7,000 were evacuated in Tamil Nadu state, the National Disaster Management Authority said.
Two navy ships with doctors, food packets and other relief material have also been put on standby, said a navy spokesman.
More than 15 teams of the National Disaster Response Force were deployed, with the storm expected to make landfall in the late afternoon close to Chennai, the state capital of Tamil Nadu.
The Tamil Nadu government ordered all educational institutions in coastal districts to be shut as a precaution.
Devastating floods last year killed at least 250 people in Chennai, India's fourth-largest city, which is home to nearly 4.6 million people.
On its way inland, Cyclone Vardah hit several islands in the Andamans last week, forcing authorities to evacuate hundreds of stranded tourists from the archipelago.
India's eastern coast and neighbouring Bangladesh are routinely hit by bad storms between April and December that cause deaths and widespread property damage.
In 1999, more than 8,000 people were killed when a cyclone battered the eastern state of Orissa.