Trump said Joe Biden, his Democratic challenger in the November 3 elections, had not specifically disavowed far-left activists accused of civil disorder.
On Monday, Trump blamed Mr. Biden and his allies for violence in cities run by Democratic mayors and governors.
At a news conference, Republican President was asked whether he would condemn Trump supporters who had fired paint pellets during a confrontation with counter-protesters at the weekend in Portland, Oregon.
Trump said, for the ensuing street clashes, that the protest is as peaceful and said paint was a defensive mechanism, paint is not bullets.
Trump also said, “Your supporters and they are your supporters indeed, shot a young gentleman. Killed him, not with paint but with bullet. And think its disgraceful.”
Biden forcefully condemned , on Monday, for the violence at recent protests while accusing Trump making the country unsafe.
Biden said, “Do I look like a radical socialist with a soft spot for rioters? Really?”
Mr. Biden’s remarks represented a pivot from his main line of attack so far, that the White House has mishandled its response to the coronavirus pandemic, which has killed more than 180,000 people in the US.
He also added, “He may believe mouthing the words law and order makes him strong but his failure to call on his own supporters to stop acting as an armed militia in this country shows how weak he is.”
Biden asked, “Does anyone believe there will be less violence in America if Donald Trump is re-elected?”
Research by Marquette University Law School in Milwaukee, Wisconsin, on 11 August found support for the racial justice protests has fallen 13 percent points, and for Black Lives matter by 10 points, from June to August.
Since the shooting of Blake in Wisconsin on 23 August reignited civil strife, Mr. Biden and his campaign have renewed their criticism of violence at demonstrations.
According to the Associated Press News Agency, Biden has been prodded by anxious Democrats, including within his campaign to be more vocal in denouncing protest-related violence.
Biden has always spoke put against violent protests a number of times between May and July.