A tropical storm warning has been issued for the coast of Mexico as Hurricane Bud gains strength in the Pacific.

The tropical storm warning is in effect early Thursday for Mexico's Pacific coast from Punto Telmo to Cabo Corrientes. A hurricane watch has also been issued for that area.

Bud's maximum sustained winds have increased to near 85 mph (140 kph) with additional strengthening expected during the day. The U.S. National Hurricane Center in Miami says gradual weakening is expected to begin by Friday.

The hurricane is centered about 350 miles (560 kilometers) southwest of Manzanillo, Mexico, and is moving north near 7 mph (11 kph).