Mexican security and immigration authorities have stepped up patrols, highway checkpoints and raids in southern Mexico since the United States started expelling Venezuelan migrants last month.
The Mexican government has not said whether its enforcement actions near its border with Guatemala are related to the U.S. policy change, which effectively shuts the door to Venezuelans trying to enter the U.S. through Mexico, but the efforts have put migrants in this southern city on edge.
Authorities have also been more active in breaking up small migrant caravans that try to advance north from Tapachula.
For months, the government seemed to encourage small groups of migrants to leave Tapachula, to relieve the building pressure and frustration there. It established an immigration center that issues temporary documents 180 miles to the northwest in San Pedro Tapanatepec.
But a small caravan that was scheduled to leave Monday had only 100 migrants. And authorities broke up two small caravans that had left the previous week after letting them walk for about 90 miles.