MEXICO CITY, May 7 (Xinhua) -- At least five people were killed and about 30 others injured Thursday in a fire at a shopping mall in northwestern Mexico, local media reported, citing authorities.

The fire was reported on Thursday afternoon at Plaza Fiesta Las Palmas, a shopping mall in the city of Los Mochis, state of Sinaloa.

Jesus Serrano, deputy prosecutor of Sinaloa's northern region, told local media that four bodies had been identified and that authorities were told that "there is one more."

"We will contact the victims' families," said Serrano. "This will be a very lengthy processing operation."

Citing witnesses, local media reported that the fire may have started in the kitchen of a restaurant inside the mall and spread quickly because of flammable materials in the building.

The Sinaloa state prosecutor's office said on social media that the injured had been taken to nearby hospitals for treatment.

Authorities are investigating the exact cause of the fire.