Mexican authorities blocked a US military plane from deporting illegal migrants on Thursday after Donald Trump's immigration crackdown began.
American officials told NBC News a packed jet never took off after authorities south of the border rejected the move.
The flight was one of three that were set to take off on Thursday, alongside two Guatemala-bound Air Force C-17s carrying over 150 people, as part of what Trump has described as the largest mass deportation effort in US history.
Deporting migrants to foreign countries requires permission from the incoming nation's government, which Mexico declined on Thursday.
It is not clear why Mexican authorities moved to block the flight, which came hours after an American hiker was also shot by suspected Mexican cartel members in California a few hundred yards north of the border.