Colombian President Gustavo Petro announced that Colombia was suspending permission for previously authorized U.S. deportation flights to land in Colombia. Ostensibly driving Petro’s action were concerns that Colombian nationals were not being treated with respect during the deportation process because they were being transported by military aircraft.

Deportation flights between the U.S. and Colombia have resumed following a dispute between the two countries that nearly led to a trade war.

The president authorized the military to assist in deportations. The planes triggered a crisis between the United States and Colombia, and prompted questions. Here’s what to know.