Some 17,000 soldiers and police have been deployed in the Mexican resort city of Acapulco, where there has been widespread looting since a powerful hurricane hit the region.
Videos show people taking food and water from shops, while others walk away with expensive electronic items and clothes from shopping centres.
Thirty-nine people are now known to have died in Hurricane Otis.
Hundreds of thousands of people remain without power and water.
Otis made landfall on the Pacific coast on Wednesday, with winds reaching 165mph (266 km/h). It had intensified from a tropical storm into a category five hurricane – the most severe category – in just 12 hours.
Acapulco was among the areas worst hit in Mexico, with 80% of the resort’s hotels damaged and streets flooded.
The death toll rose to 39 on Saturday – 29 men and 10 women, the government said, while at least 10 are missing.
Videos have been uploaded to social media showing looting in hard-hit neighbourhoods as food and water supplies run increasingly low.
The main road linking Acapulco to the rest of the country has only now been reopened, allowing the delivery of essential goods to the city.
In the Renacimiento neighbourhood, residents have been left angered by the lack of aid.
“The government hasn’t given us any help, not even hope,” Apolonio Maldonado told Reuters news agency, lifting his feet from the water to show deep red cuts on his shins.
“They haven’t left any food, or even mattresses or cots.”
President Andrés Manuel López Obrador has promised to help rebuild the city, but has accused his political rivals of exaggerating the extent of the looting to discredit his government before next year’s presidential election.
“They circle like vultures, they don’t care about people’s pain, they want to hurt us, for there to have been lots of deaths,” he said in a video uploaded to social media.
Officials say Otis was the most powerful storm to ever hit Mexico’s Pacific coast, leaving a trail of devastation estimated at billions of dollars.