US president Donald Trump's younger brother Robert Trump was laid to rest at a rare White House memorial service on Friday. Trump along with his wife Melania Trump and other family members were present at the ceremony.

The president and first lady Melania Trump emerged from the White House hand in hand and were seen following Robert Trump's casket to the hearse as a bagpiper played a hymn in the North Portico. The service was held at the East Room, a White House source told CNN.

Donald Trump, 74, was dressed in a navy suit with white shirt and back tie, white the first lady of the US, 50, was also solemnly dressed in a black outfit with matching thin belt and high heels. The first couple was joined by several members of his family at the service – a very rare event in White House history.

Funerals are rare at the White House. The last appears to have been for President John F. Kennedy in 1963. White House officials said the president personally covered the expenses of the memorial service for his brother.

At the service, Trump did not make any comments about his brother Robert. But, the POTUS later tweeted: "Robert, I Love You," and "Rest In Peace!"

Earlier in the day, Trump briefly mentioned his brother, telling an audience in Virginia that "my brother, Robert, would have wanted me to be here today."

Robert Trump, 71, died on Aug. 15, Saturday of an undisclosed illness. This came just a day after the president made an unscheduled visit to him in a New York hospital. The youngest of the Trump siblings, Robert Trump was also hospitalised in the intensive care unit at Mount Sinai hospital in New York for more than a week in June.

Trump once fondly described his younger brother Robert as "much quieter and easygoing than I am," and "the only guy in my life whom I ever call 'honey.'"

Robert began his career on Wall Street working in corporate finance but later joined the family business, Trump Organization. He managed real estate holdings as a top executive. He spent 20 years working in the family business before retiring and was living in Long Island for the last few years.

Robert and Donald Trump in 2016
Then president-elect Donald Trump hugs his younger brother in 2016. Photo: GETTY IMAGES NORTH AMERICA / CHIP SOMODEVILLA

He was married to Blaine Trump for 25 years, but they divorced in 2008. Robert was a strong supporter his older brother and always kept a low profile.