At least 27 people died due to Hurricane Otis and four others were still missing, Mexico's government said on Thursday after one of the most powerful storms to hit the country smashed into the Pacific beach resort of Acapulco early the day before.

President Andres Manuel Lopez Obrador said the government was working to re-establish power and clean up the devastation wrought by the Category 5 hurricane that tore through the southern state of Guerrero, leaving Acapulco incommunicado.

"What Acapulco suffered was really disastrous," Lopez Obrador told a regular government press conference.

Otis flooded streets, ripped roofs off homes and hotels and severed communications, road and air access.

Downed phone service and electricity lines made it hard for officials to quickly assess the extent of the damage.

Nearly 8,400 members of Mexico's army, air force and national guard were deployed in and near Acapulco to assist in cleanup efforts, the defense ministry said.

Classes were canceled for students across the state for a second day, and Governor Evelyn Salgado said on social media that authorities were working to restore electricity and reactivate drinking water pumps in Acapulco.

Mexico's state power utility CFE had over 1,300 employees working to restore power, it said on Wednesday evening, when some 300,000 people remained without electricity.

The port city's international airport was closed after Otis wrecked the control tower, cut telecommunications and left access roads blocked.