U.S. military and police forces began the first deportation flights for illegal immigrants under President Donald Trump's hardline immigration crackdown nationwide and particularly at the southern border.

U.S. military C-17 aircraft began flying detained migrants out of the country on Friday, following orders from President Donald Trump, as the Pentagon prepared to send more troops to the southern border,

Colombia has denied entry to two U.S. military deportation flights, according to officials from the Department of Homeland Security and the Defense Department. The flights, carried out on U.S. military C-17 aircraft, were carrying about 80 Colombian migrants each and had departed from California, the defense official told NBC News.

Mexico has refused a request from President Donald Trump's administration to allow a U.S. military aircraft deporting migrants to land in the country, a U.S. official and a Mexican official told Reuters.