Four people have died, and nearly 40 have been hospitalized after drinking tainted tequila at a girl's quinceañera in Mexico, local officials said.

The quinceañera, a traditional Latin American girl's 15th birthday party, was held at a party hall in Salamanca in the state of Guanajuato on Saturday, according to local news outlet AM.

Several of the victims were relatives of the birthday girl, who was identified only by her first name, Jazmín.

The four people who were killed have been identified as Jazmín's father, José Antonio Cárdenas, 39, her uncle, Martín Robles, 28, and two other guests, Sanjuana González, 36, and José Guadalupe Ramblás, 33.

Local news outlets reported that the day after the party, many of the guests' families thought they were hungover, but after they remained asleep for hours, they realized their loved ones were unconscious. 

Ramblás' grandfather, Narciso López, confirmed his passing and said that another one of his grandsons was also poisoned by the tainted alcohol, but was 'doing well', and demanded that 'justice must be served.'

'They tell me my grandson was asleep and stayed that way all Sunday, until they saw he wasn't waking up. They took him to the hospital and they tell me he's dead,' he told Periódico Correo.

Ramblás was also remembered by his soccer league, the Liga De Fútbol Valtierrilla, in a Facebook post.

One of González' friends told AM she worked as a food vendor, and people became concerned when she did not show up to sell tamales two days after the party.

'She was very well known here,' they told the outlet. 'She always went to work early in Puerto de Valle, but on Monday she didn't show up to sell, and then we found out about this. We want to know what happened.'

According to Periódico, 28 people who were poisoned at the party were treated at the Hospital de la Gente in Salamanca.

Eight others were treated at the Mexican Social Security Institute and two at another Hospital de la Gente.

Six remained in the hospital as of Tuesday, June 9, according to the outlet.

Authorities are working to identify the source of the tequila, but sources told AM that it is up to the Guanajuato State Attorney General's Office to continue the investigation.

The US State Department has issued a level 3 reconsider travel advisory to Guanajuato since 2023 due to terrorism, crime, and kidnapping.

'Gang violence in Guanajuato mostly happens in the southern and central areas,' the state department said.

'There is a high number of murders in the southern region due to cartel-related violence.'

Salamanca is located in the south-central part of the state of Guanajuato.