US President Donald Trump returned to the White House on Monday night after spending four days at a military hospital where he was treated for COVID-19.

Trump, 77, looked healthy. Showing his fitness, Trump in an unusual decision climbed up the South Portico stairs, instead of the elevators, to go to his residence.

The president took off his mask, stood up in the portico facing South Lawns for a few minutes, and saluted Marine One.

Earlier, he was discharged from the Walter Reed National Medical Center after doctors treating him found that he was fit enough to go back home.

"Will be back on the Campaign Trail soon!!! The Fake News only shows the Fake Polls," Trump said in a tweet moments before leaving Walter Reed National Medical Center in Bethesda, a Maryland suburb of Washington DC.

His former White House Press Secretary Sarah Sanders said the president was strong and upbeat. "He's a fighter and will not quit battling this virus or surrender to the liberal mob and forces out to destroy our country," Sanders said in a tweet.

Before boarding Marine One at Walter Reed, Trump told reporters that he was feeling good.