The US Grammy-nominated artist was arrested in Sweden in connection with a street fight that occurred in June.
The President said he had been in touch with Swedish Prime Minister Stefan Löfven about the matter.
He tweeted: “Just had a very good call with Stefan Löfven who assured me that American citizen ASAP Rocky will be treated fairly.
“Likewise, I assured him that ASAP was not a flight risk and offered to personally vouch for his bail, or an alternative.
Just had a very good call with @SwedishPM Stefan Löfven who assured me that American citizen A$AP Rocky will be treated fairly. Likewise, I assured him that A$AP was not a flight risk and offered to personally vouch for his bail, or an alternative....— Donald J. Trump (@realDonaldTrump)July 20, 2019
“Out teams will be talking further, and we agreed to speak again in the next 48 hours!”
Mr Trump said the phone call came after he was in touch with Kanye West, after previously tweeting “So many people would like to see this resolved quickly!”
Just spoke to @KanyeWest about his friend A$AP Rocky’s incarceration. I will be calling the very talented Prime Minister of Sweden to see what we can do about helping A$AP Rocky. So many people would like to see this quickly resolved!— Donald J. Trump (@realDonaldTrump)July 19, 2019
Rocky, a 30-year-old performer, producer and model, whose real name is Rakim Mayers, was detained on July 3 along with his bodyguard and two other members of his entourage in connection with a fight in a Stockholm city-center street in the early hours of June 30.
The performer was in Stockholm for a concert and has had to cancel several shows in his European tour.
ASAP Rocky (Getty Images for LACMA)
A spokesman for Löfven emphasized the Swedish government "will not attempt to influence" legal case.
"In Sweden everyone is equal before the law," said Toni Eriksson, a Swedish spokesman for Löfven.
Mr Eriksson said: "The government cannot and will not attempt to influence the legal proceedings."