US President Donald Trump’s younger brother, Robert Trump, has died a day after the President visited him in a New York hospital.

Robert Trump with then-wife Blaine in 2003. Photo: Getty

“It is with heavy heart I share that my wonderful brother, Robert, peacefully passed away tonight,” Mr Trump said in a statement.

“He was not just my brother, he was my best friend.

“He will be greatly missed, but we will meet again. His memory will live on in my heart forever.

“Robert, I love you. Rest in peace.”

Robert Trump, who at 72 was two years younger than the president, was a business executive and real estate developer.

President Trump made an emotional visit to see his ailing brother on Friday at New York-Presbyterian/Weill Cornell Medical Centre before going to his golf club at Bedminster, New Jersey, for the weekend.

The future president gives brother Robert a quizzical look at a 1999 NYC gala. Photo: AP

No cause of death has been reported, leading to social media speculation the First Brother died of COVID-19.

Why has the cause of Robert Trump’s hospitalization and death not been mentioned?

— Helen Kennedy (@HelenKennedy) August 16, 2020

The New York Times reports that Robert Trump, who was known to be taking prescription blood thinners, had been diagnosed with bleeding on the brain after a recent fall.

Over the past few weeks, he had not been able to speak on the phone, according to the family friend.

The President was expected to attend the funeral, an aide said.

-with AAP