TAPACHULA, Mexico — 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.

Still, many are finding a way to move north. Thousands of migrants await temporary documents at the immigration center housed in large tents in San Pedro Tapanatepec.

Savi Arvey, senior policy adviser for the Migrant Rights and Justice Program at the Women’s Refugee Commission, visited the camp last week. She said there were an estimated 12,000 to 17,000 migrants waiting there for temporary immigration documents that limited migrants to moving around the state of Oaxaca.

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