US President Donald Trump on Saturday said demonstrators protesting the death of a black man who died after a white police officer knelt on his neck would have been “greeted with the most vicious dogs, and most ominous weapons, I have ever seen” had they breached the White House fence.

In a series of Twitter posts, Trump also appeared to call his supporters to rally outside the executive mansion on Saturday evening, saying, “TONIGHT, I UNDERSTAND IS MAGA NIGHT AT THE WHITE HOUSE???” MAGA stands for Trump’s slogan “Make America Great Again.”

The death on Monday in Minneapolis of George Floyd has sparked demonstrations in many cities across the nation, including one in Washington on Friday.

The White House was temporarily locked down as hundreds of people gathered in the afternoon across the street in Lafayette Square. After marching away, demonstrators assembled again later and videos showed pushing-and-shoving matches between officers and protesters, who dispersed early on Saturday.

Trump praised the US Secret Service officers who guard the White House as “very cool. I was inside, watched every move, and couldn’t have felt more safe.”

“Big crowd, professionally organised, but nobody came close to breaching the fence. If they had they would have been greeted with the most vicious dogs, and most ominous weapons,” he said.

Trump accused Washington DC mayor Muriel Bowser of refusing to send police to help the US Secret Service. Reuters, although the Washington Post reported that city officers did help control the later gathering.

On Friday, Trump drew a warning from Twitter and condemnation from Democrats after posting a comment that “looting leads to shooting”.