MEXICO CITY (Reuters) - Hurricane Bud, the first hurricane in the 2012 Pacific season, strengthened into a major Category 3 storm on Thursday and was headed toward Mexico's coast, the U.S. National Hurricane Center said.

With maximum sustained winds of 115 mph, Bud is threatening to dump heavy rains around the port city of Manzanillo, the Miami-based center said.

(Reporting by Mica Rosenberg; editing by Mohammad Zargham)