Kirk was located in the central Atlantic Ocean and could strengthen even more over the next day or so, but was expected to remain away from land, the Miami-based U.S. National Hurricane Center said.
Swells generated by Kirk were expected to reach portions of the Leeward Islands on Friday, Bermuda and the Greater Antilles on Saturday, and the East Coast and the Bahamas on Sunday, the center said.
There were no coastal watches or warnings in effect. The major hurricane was about 1,085 miles (1,745 kilometers) east-northeast of the Northern Leeward Islands with maximum sustained winds of 130 mph (215 kph).
Meanwhile, Tropical Storm Leslie formed late Wednesday in the eastern Atlantic and could strengthen into a hurricane on Friday, forecasters said. It also was not yet deemed a threat to land.