MEXICO CITY, Dec 2 (Reuters) - Migrant shelters in northern Mexico said on Thursday they fear they will be overwhelmed by an influx of asylum seekers next week when the United States resumes a Trump-era program to return them to Mexico. U.S. President Joe Biden had tried to end the policy as part of a more humanitarian approach to migration, but federal courts ordered a reboot of the so-called Migrant Protection Protocols (MPP), which require asylum seekers to wait in Mexico for U.S. immigration hearings. Mexico said Thursday it had agreed to a restart. The returns will likely begin Monday at a single border crossing and eventually expand to a total of seven. Shelter directors said that could spark an influx of people to their facilities at a time of record migration from Latin America and the Caribbean. "We are saturated with the arrival of Haitians ... Central Americans and hundreds of Mexicans displaced by violence," said Jose Garcia, director of the Juventud 2000 shelter in Tijuana, one of the cities where asylum seekers are expected to be sent. The coronavirus pandemic had already forced him to reduce capacity, he added. Local officials also expressed concern about where funding will come from to absorb migrants waiting for U.S. hearings. "The federal government hasn"t notified us that it will help out with a bigger budget," said Carmen Canturosa, mayor of Nuevo Laredo, a border city notorious for crime and violence. Both U.S. and Mexican officials said the United States will address Mexico"s humanitarian concerns about the revamped program. Still, rights" advocates say the policy exposes migrants to serious risks. "They are returning them to cities that represent a danger to these families due to criminal and cartel violence," said Fernando Garcia, director of the Border Network for Human Rights in El Paso, Texas. Since the program began in 2019, tens of thousands of people have been sent back to Mexican border cities, where many waited months and sometimes years in makeshift camps or bare-bones shelters without access to jobs or schools. Guatemalan migrant Andrea Lopez said it made her sad to think of more asylum seekers being put in her situation. She has spent the last several months in an encampment in Tijuana with her two children after requesting asylum across the border. "We can"t even work," she said. "Everything here is very dangerous."