Dramatic footage has emerged showing the moment a Mexican Navy helicopter plummeted into the water.
One person is missing and two were injured in the crash, which happened in the Gulf of Santa Clara, according to reports.
A further nine people were unharmed, it is understood.
The MI-17 chopper was patrolling the area in order to combat illegal fishing, El Mexicano reports.
Several fisherman rushed to help the stricken crew after the helicopter hit the water.
Two injured people were taken to San Felipe for medical treatment.
The footage shows the aircraft veer to its side before slowly descending as the pilot was unable to bring it back under control.
An investigation is underway to determine what caused the chopper to crash at around 3.30pm on Saturday.
A Navy spokesman said, according to Valortamaulipeco : "This institution is grateful for and recognises the prompt and timely response of the fishermen who supported the work for our naval personnel."
And he continued: "The Navy regrets the accident and will provide the necessary medical attention to the naval personnel, as well as confirming its commitment to maintain operations in sensitive areas... and continue contributing to the eradication of illegal activities in national waters."
A search is being carried out for the missing person, who has not been identified in Mexican media.