(Updates with new strength, position and dateline)
PUERTO VALLARTA, Oct 22 (Reuters) - Hurricane Patricia strengthened into an "extremely dangerous" Category 5 storm late on Thursday as it churned toward Mexico's Pacific coast, the U.S. National Hurricane Center (NHC) said.
The storm, which became a hurricane overnight, had maximum sustained winds of about 160 miles per hour (260 km per hour) as it moved toward the north-northwest at 10 mph (16 kph).
Patricia was last located about 200 miles (320 km) south-southwest of the port of Manzanillo, where a hurricane warning had been issued. A hurricane warning was also in effect for the beach resort of Puerto Vallarta.
The storm, which is a "Category 5", the highest rating possible, is expected to weaken somewhat before making landfall in the hurricane warning area by Friday afternoon or evening, the Miami-based hurricane center said.
The United States government issued an advisory urging its nationals to steer clear of beaches and rough seas, and to take shelter as instructed by Mexican officials.
Some businesses in Puerto Vallarta had begun boarding and taping up windows late on Thursday as a precaution, while several domestic flights had been delayed.
Mexican emergency officials began to prepare shelters and warned people in the states of Colima, Jalisco and Michoacan to get ready for torrential rainfalls.
None of the major installations of Mexican state oil giant Pemex lie in the projected path of the storm. (Reporting by David Alire Garcia; Editing by Simon Gardner and Edwina Gibbs)
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