Karina strengthens into a Category 4 hurricane in the Pacific far from land, forecasters say

Hurricane Karina strengthened Monday into a powerful Category 4 storm in the Pacific Ocean but isn't threatening land, forecasters said.

The storm has intensified quickly since becoming a hurricane Sunday and has been fueled by warm waters far offshore, the U.S. National Hurricane Center in Miami said.

Karina was about 1,020 miles (1,642 kilometers) west-southwest of the southern tip of the Baja California peninsula of Mexico and had maximum sustained winds of 145 mph (233 kph), the center said.