Mexico has refused to allow a US military plane carrying deportees to land on its territory .

After taking office on Monday, US President Donald Trump declared an emergency at the southern border and vowed to ramp up deportations of illegal migrants.

NBC News cited two US defense officials and a third source as saying that a C-17 military transport plane carrying an unspecified number of migrants was scheduled to land in Mexico, but never took off.

Two similar flights to Guatemala with around 80 migrants aboard each proceeded as planned on Friday.

A Mexican official confirmed that the US plane was not granted permission to land in the country. He did not provide a reason for the denial .

The Mexican Foreign Ministry did not explain why the plane was barred from landing in the country in a statement on Friday. It only said that “Mexico has a very good relationship with the US government and we cooperate with respect for our sovereignty on a wide range of issues, including migration.”

“When it comes to repatriations, we will always welcome the arrival of Mexicans to our territory with open arms,” the ministry stated.

Under Trump’s order, the Pentagon earlier dispatched 1,500 more soldiers to help southern border agents to monitor and process migrants. The new administration also said it is re-launching the ‘Remain in Mexico’ program, according to which non-Mexican asylum seekers should wait in Mexico while their cases are being processed in the US.

The new US president has also declared Mexican drug cartels terrorist organizations, renamed the Gulf of Mexico to the Gulf of America, and threatened to slap 25% tariffs on Mexican goods starting from next month.