Storm Gabrielle has strengthened into a major hurricane in the Atlantic Ocean but was forecast to remain away from land.

The Miami-based National Hurricane Center said Gabrielle's maximum sustained winds were 120 mph (191 kph), making it a dangerous Category 3 hurricane.

The storm was located about 180 miles (290 kilometres) southeast of Bermuda. It was moving north at about 10 mph (16 kph).

Gabrielle had become a Category 1 hurricane on Sunday before it underwent intensification in warm Atlantic waters. The storm's path was taking it east of Bermuda.

Swells from the storm reached Bermuda and were impacting the US East Coast, from North Carolina northward to Canada's Atlantic coast. Forecasters said the swells were likely to cause "life-threatening surf and rip current conditions."

This year's Atlantic hurricane season has been relatively quiet and before Gabrielle there was only one named hurricane in that ocean. Experts say there's a few reasons for that, but it doesn't mean dangerous systems won't form later.

The Atlantic hurricane season ends November 30.