Hurricane Igor was at Category 4 strength with winds near 150 mph, but the National Hurricane Center in Miami said Hurricane Igor could reach Category 5 strength today.
Igor was located about 940 miles (1,515 kilometers) east of the Northern Leeward Islands and was moving west near 13 mph (20 kph). A turn toward the west-northwest was expected Monday night or Tuesday, the hurricane center said.
Also in the Atlantic, Tropical Storm Julia was moving westward, away from the southern Cape Verde Islands. Julia was about 85 miles (130 kilometers) west-southwest of the southernmost islands and moving west-northwest near 14 mph (23 kph). The storm's maximum sustained winds were near 40 mph (65 kph).
Officials issued a tropical storm warning for parts of the Cape Verde Islands including Maio, Sao Tiago, Fogo and Brava.
IN PICTURES: Huge hurricanes