Mexican negotiators convinced President Trump to back down from his tariff threat by agreeing to an unprecedented crackdown on Central American migrants and by accepting more-expansive measures in Mexico if the initial efforts don’t deliver quick results, according to officials from both governments and documents reviewed by The Washington Post.

The enforcement measures Mexico has promised include the deployment of a militarized national guard at the Guatemalan border, thousands of additional migrant arrests per week and the acceptance of bus loads of asylum seekers turned away from the U.S. border daily, all geared toward cutting the migrant flow dramatically in coming weeks. The measures, described by officials from both sides and included in Mexican negotiating documents reviewed by The Post, appear to be more substantial than what the Mexican government has attempted thus far during the precipitous rise in migration to the U.S. border.

Since heralding the pact in a Friday night tweet, Trump has fumed at criticism that he capitulated to Mexico and that his accord amounts to a series of previously agreed-to measures.