Mexican authorities have arrested three suspects in the murder of an eight-year-old girl, after an outraged mob in the tourist town of Taxco lynched a woman accused in the crime.

A man and a minor were arrested on Saturday "for the crime of femicide", Guerrero state prosecutors said in a press statement, along with another man the day before on similar charges.

The girl's family had received anonymous telephone calls demanding a ransom after she disappeared on Wednesday, Mexican media reported, quoting a relative.

Residents on Thursday blocked one of the main streets of Taxco, which has been plagued by organised crime, after the child's body was found on a highway.

Security camera footage had circulated earlier showing suspects allegedly putting a black bag in the trunk of a car, prompting suspicions that it contained the girl's body.

A mob gathered outside a house where a woman and two men were located, demanding justice. They dragged out the trio, doused them in gasoline, and beat them with sticks.

The woman died and the two men were hospitalized.

The prosecutor's office did not clarify whether the men attacked by the angry mob were among those arrested.

"My solidarity is with the family (of the minor), the future is not understood without justice," the governor of Guerrero, Evelyn Salgado, said Friday on X, formerly Twitter. 

Worsening crime in Taxco led the United States in January to ban its government employees from visiting the city, located about 170 kilometres from Mexico City.

Kidnappings and murders are daily occurrences in Mexico, although adult men are the most common victims, making the young girl's death particularly shocking.

There are regular lynchings of alleged criminals, which experts link to the widespread perception of impunity in the crime-wracked country.

A report by researchers at the Autonomous University of Mexico found that 1,423 lynchings were recorded between 2016 and 2022.