Donald Trump threatened to send US troops to Mexico to deal with "bad hombres down there" in a call with President Enrique Peña Nieto, according to a partial transcript of the call seen by the Associated Press.

Mr Trump used similar rhetoric while campaigning for the presidency, but such a warning in a call with an allied world leader would mark an extraordinary departure from decorum, in addition to the obvious violation of Mexico's sovereignty that enforcing it would entail.

"You have a bunch of bad hombres down there," Mr Trump told Mr Pena Nieto, according to the excerpt. "You aren't doing enough to stop them. I think your military is scared. Our military isn't, so I just might send them down to take care of it."

The White House and the Mexican foreign ministry both denied that Mr Trump made the threat.

The Mexican website Aristegui Noticias on Tuesday published a similar account of the phone call, based on the reporting of journalist Dolia Estevez. The report described Mr Trump as humiliating Mr Pena Nieto in a confrontational conversation.