Soldiers keep watch at a beach as Hurricane Otis barrels towards Acapulco, Mexico, on Tuesday. Reuters

Mexico's southern coast braced for Hurricane Otis on Wednesday as the Category 5 storm made landfall near the beach resorts of Acapulco, with the potential to cause "catastrophic damage," the US National Hurricane Center (NHC) said.

The hurricane reached land near Acapulco, bringing maximum sustained winds around 165 mph (270 kmh) and heavy rain, the center said.

The storm could bring up to 20 inches (51 cm) of rain in parts of Guerrero and Oaxaca, with the possibility of flash floods and mudslides, a "potentially catastrophic" storm surge, and "life-threatening" surf and rip current conditions, authorities said.

Mexico's national water agency CONAGUA warned of six-to-eight-meter surf off Guerrero state, home to Acapulco, and also off parts of Oaxaca state.

By 9 p.m. on Tuesday (0300 GMT), Otis was about 55 miles south-southeast of Acapulco and blowing maximum sustained winds of 160 mph (257 kph), the Miami-based NHC added.

In Guerrero, authorities were preparing storm shelters and the national guard said it was helping to prepare for rescues and evacuations.

The defense ministry enacted a disaster plan ahead of the storm's arrival, President Andres Manuel Lopez Obrador said on social media late on Tuesday, as soldiers patrolled Acapulco's emptying beaches.

Schools across Guerrero canceled classes for Wednesday ahead of Otis' arrival, Governor Evelyn Salgado said on social media.

Reuters