A powerful coastal storm left more than 600,000 homes without power in the northeastern United States on Wednesday, forecasters said, reports AFP.

The state of Massachusetts was the hardest hit, with 466,000 homes without power as of 8:00 am (1200 GMT).

The National Weather Service called the situation dangerous and warned of hurricane-type gusts of wind and many uprooted trees.

"Travel is not recommended," said the NWS office in Boston.

Rhode Island was also badly affected, with 91,000 homes without electricity.

The NWS said the situation should improve toward the end of the day and that the storm "will move farther offshore tonight."