Tropical Storm Maria was gathering energy from warm ocean water but remained over the open Atlantic on Saturday and posed no immediate threat to land.
The U.S. National Hurricane Center said Maria could become a hurricane late Saturday or Sunday.
At 5 p.m. EDT (2100GMT), the storm had maximum sustained wind of 70 mph (112 kph) _ 20 mph (32 kph) higher than its measured speeds earlier Saturday morning _ and was centered 760 miles (1200 kilometers) northeast of the northern Leeward Islands, about 740 miles (1200 kilometers) southeast of Bermuda.
It was moving northwest, a track that could take it east of Bermuda, at 16 mph (25 kph), forecasters said.
Maria would be the season's fifth hurricane if its sustained wind speed reaches 74 mph (120 kph).
Maria is the 13th named storm of the Atlantic hurricane season, one of the busiest on record. Historically, only about four or five named storms form by this time of year. Peak storm activity typically occurs from the end of August through mid-September, AP reported.