A drone view shows stacked containers at the port of Manzanillo, as Hurricane Simon approaches Mexico's Pacific coast. [Photo Credit: Reuters]

Hurricane Simon strengthened into a powerful Category 4 storm off Mexico’s Pacific coast on Saturday, threatening destructive ‌winds, storm surges and potentially deadly flooding as it approaches landfall.

The US National Hurricane Center said Simon was located about 115 miles (185 km) south-southwest of Manzanillo, Mexico, on Saturday morning, packing maximum sustained winds of 150 mph (240 kph) as it moved northward.

Simon is expected to approach the west-central coast of Mexico as a major hurricane late on Saturday ​or early Sunday, and some additional strengthening remains possible before landfall, the NHC said.

A hurricane warning was in effect for portions of Mexico’s ​Pacific coast south of the beach resort of Puerto Vallarta, including the area around Manzanillo, Mexico’s largest Pacific port. ⁠A tropical storm watch was in effect farther south toward Lazaro Cardenas.

The NHC urged residents in the warning area, which also includes the Islas ​Marias archipelago offshore, to rush preparations to protect life and property.

In the early afternoon on Saturday in Manzanillo, residents appeared largely calm despite ​the approaching storm, with little sign of panic buying at supermarkets, according to a Reuters reporter on the ground. Some stores had begun boarding ​up their windows, while businesses were closing and streets were relatively empty. Rain had been falling intermittently since late on Friday, and rising seas were pushing waves almost to ‌the ⁠entrances of beachfront hotels, although strong winds had yet to arrive.

Civil protection workers had closed beaches, erected barriers and raised red and black warning flags, urging residents to stay away from the shore. Marines, soldiers, National Guard officers and emergency personnel were patrolling areas vulnerable to flooding and landslides, while authorities had begun precautionary evacuations in parts of Cihuatlan, a flood-prone municipality in neighboring Jalisco state, near Manzanillo. Rivers in some areas were already running high, raising ​concerns they could overflow if heavy ​rains intensified.

Mexican authorities warned that heavy ⁠rainfall was expected in the states of Guerrero, Michoacan, Colima and Jalisco.