As many as 1,000 Central American migrants marched toward Tapachula, Chiapas, after crossing the Suchiate River at the border with Guatemala early Thursday.
The largest caravan of migrants to enter Mexico since President López Obrador agreed last year to reduce the flow of migrants to the U.S. marched over seven kilometers into Chiapas this morning.
But that was as far as they got.
National Guardsmen and immigration agents erected a barrier on the highway outside Tapachula and fired tear gas at the migrants when they approached.
Some were detained but many remained in the community of Frontera Hidalgo where they were making plans to submit a petition to López Obrador to ask for asylum.
On Monday, after the National Guard stopped migrants from crossing the international bridge into Ciudad Hidalgo, Chiapas, hundreds attempted to wade across the Suchiate River.
Guardsmen used tear gas and batons to repel the majority and later detained others who successfully entered the country.
President López Obrador said at his morning news conference on Wednesday that the federal government took such actions to protect the migrants from crime in the north of Mexico and insisted that the use of tear gas was an isolated incident.