As it happened: US President Donald Trump leaves hospital to return to the White House

US President Donald Trump has left hospital after his COVID-19 treatment to return to the White House.

The President tweeted that he'll be "back on the Campaign Trail soon" ahead of his departure from the Walter Reed Hospital in Maryland on Tuesday (NZ time).

"The Fake News only shows the Fake Polls," he added.

Trump was taken to hospital last week out of concern for his health after he was diagnosed with the coronavirus on Friday.

His doctors said his condition was serious enough that he required supplemental oxygen on at least two occasions. He was treated with a number of different drugs, including an experimental antibody cocktail, a steroid called dexamethasone and antiviral drug Remdesivir.

On Tuesday morning, Trump announced he would be leaving the hospital.

"Feeling really good!" he said on Twitter.

"Don't be afraid of COVID. Don't let it dominate your life. We have developed, under the Trump Administration, some really great drugs & knowledge. I feel better than I did 20 years ago!"

Wearing a face mask, the president walked out the front door, waved to supporters and gave the thumbs-up.

He refused to answers questions about if he is a superspreader before he got into a presidential vehicle and was driven to a waiting helicopter which took off.

After arriving at the White House, Trump was filmed whipping off his face mask and stuffing it in his pocket.

Shortly afterwards, the president released two videos - one of him arriving and saluting his helicopter, and another with a message to the US public.

"I just left the Walter Reed medical centre and it's really something special," Trump said in the video.

"I learned so much about coronavirus. And one thing that's for certain - don't let it dominate you. Don't be afraid of it."

Trump said he could have left hospital two days ago and he was feeling great.

"Now I'm better and maybe I'm immune, I don't know," he said. 

Trump's decision to leave hospital was criticised earlier on Tuesday with Governor of New Jersey Christine Todd Whitman saying Trump's "irresponsibility is shocking".

"Leaving 1 of the best hospitals, having received drugs the average person doesn't have access to, going home w/ full medical staff, he has the audacity to say don't fear #COVID19 & he feels better than ever? THIS is our President?!"

Trump has also been blamed for reportedly hiding a positive COVID-19 test result.

 The Wall Street Journal reports that Trump attempted to hide the results of his first positive tests.

According to its article, shortly before appearing on Fox News that Thursday, the US President received a positive result on a rapid test.

A rapid test can tell in minutes if someone is infected with the coronavirus but is less accurate.

While waiting for the results from a more complete test, Trump went on the network and failed to reveal the rapid test result, the Wall Street Journal reports.

Instead, he said an aide had tested positive and mentioned he was waiting for the results from the second test.

"I'll get my test back either tonight or tomorrow morning," the President told Fox.

After these came back positive a few hours later, Trump tweeted that he and First Lady Melania had received confirmed tests for the virus.

And according to the Wall Street Journal, Trump also attempted to keep his advisors' COVID-19 statuses secret too.

"Don't tell anyone," Trump reportedly told an infected adviser.