The wait has just begun and Tijuana is feeling the strain. With Mexico’s new federal government preparing to take office on Dec. 1, the city has received the barest minimum of help and cannot set up a new shelter, said César Palencia Chávez, who is in charge of migrants’ affairs for the city of Tijuana.

“We would all like for them to have a dignified space for the children, the women, the men, but the reality is that what has been humanely possible up to now is this,” he said, referring to the sports center. “There are no resources.”

And since the migrants won’t separate, he said, he cannot place some of them with the city’s network of largely church-run shelters.

Most of those shelters, he said, will take only women and children because publicity about the way the caravan pushed through Mexico’s southern border with Guatemala a month ago and the arrests of nearly 60 men in Tijuana during the past week — almost all for nonviolent misdemeanors — have begun to rattle citizens.

On Wednesday Mexican authorities detained a caravan of some 180 Central American migrants north of the Guatemalan border who were traveling without the proper documents, the National Migration Institute said. The migrants were given an opportunity to seek asylum in Mexico or be returned to their countries.

At the sports center shelter, supplies were stretched even before the second half of the migrant caravan arrived, despite donations from volunteer and church groups, said Delia Ávila Suárez, who heads Tijuana’s family services agency. Toilet paper, diapers, sanitary pads and cough medicine often ran out before a new delivery arrived.