This week, dozens of migrants in Mexico’s largest detention center gathered to protest over fears they will contract the coronavirus in the facility, which advocates have long denounced for overcrowding and poor sanitation. They were met with a violent crackdown by the country’s federal police and national guard, according to Mexican human rights groups. A coalition of local rights groups, the Collective for the Observation and Monitoring of Human Rights in Southeastern Mexico, on Wednesday denounced law enforcement’s response to the protest in the Siglo XXI detention center in the southern city of Tapachula, saying they beat migrants and transported them to an unknown location. “We strongly condemn all acts of violence and disproportionate use of force against people, men, women and adolescents in immigration detention,” the rights groups said in a statement. The account is the product of interviews with witnesses and victims, a representative of the groups said. Reuters was unable to independently verify the events described in the statement. The National Guard did not respond to a request for comment. A spokeswoman for the National Migration Institute (INM), which runs the facility, said the agency is working with authorities in Guatemala, Honduras and El Salvador to help migrants return home. INM “seeks to implement actions so that Central American migrants housed in migratory stations and provisional spaces of the institute can return safely to their places of origin as soon as health security measures, which include border closures, permit,” the spokeswoman said. Detainees in Siglo XXI described to Reuters last year being held in the facility near Mexico’s southern border for long periods without information about their cases, reporting severe overcrowding, sparse water and food, and limited healthcare. The center has a long history of abuses recorded by groups including the Mexican government’s human rights ombudsman. Past protests at the facility have sometimes been rowdy, and security forces have defended their operations as necessary force to restore order. As cases of the coronavirus rise in Mexico, concerns are mounting about how to prevent the spread of the disease among the thousands of migrants who have been waylaid in the country as a result of hardline U.S. immigration policies. Mexican detention centers are seen as particularly vulnerable. “They don’t comply with minimum health standards even in the best of times,” said Daniel Berlin, a deputy director for rights group Asylum Access. “It doesn’t surprise me at all that people are extremely frightened.” Asylum Access wrote INM last week asking about its plan to contain the coronavirus in the facilities but has yet to receive a response, Berlin said, adding that he did not know the specifics of the situation at the Tapachula center. In recent weeks, some advocates have suspended their visits to detention centers as a precaution against coronavirus, “which leaves people even more vulnerable,” Berlin said. The conflict in Siglo XXI arose on Monday when 50 to 70 migrants, primarily from Honduras and El Salvador, gathered to protest long detention times, the rights groups in southern Mexico said. “People expressed fear of contracting the COVID-19 virus and announced their intention to start a hunger strike if they were not released,” the rights groups said. National Guard and INM officers deployed poles, water hoses, pepper spray and Tasers against migrants, according to the groups.