Donald Trump fired back at Barack Obama after portions of the former president's Wednesday evening Democratic National Committee addressed surfaced that were harshly critical of the incumbent. He dubbed Mr Obama as a "terrible" chief executive, and said his "ineffective" two terms were the reason voters put him in the White House four years ago.

"I see the horror that he's left us. The stupidity of the transactions that he made," Mr Trump replied to a reporter during a coronavirus briefing.

"How bad he was," the 45th president said of the 44th, calling Mr Obama "so ineffective" and "so terrible."

The president then contended if Mr Obama and former Vice President Joe Biden, the designated 2020 Democratic presidential nominee, had not done such a poor job, he would not have been elected in the first place. Mr Trump ran largely on a complete repudiation of the Obama administration's raft of domestic and foreign policies.

His comments came in response to what Mr Obama will say later in the night during the Democratic Party's 2020 nominating convention.

"I did hope, for the sake of our country, that Donald Trump might show some interest in taking the job seriously, that he might come to feel the weight of the office and discover some reverence for the democracy that had been placed in his care," Mr Trump will tell voters around 10:30 p.m.

"But he never did. He's shown no interest in putting in the work, no interest in finding common ground; no interest in using the awesome power of his office to help anyone but himself and his friends, no interest in treating the presidency as anything but one more reality show that he can use to get the attention he craves," the former president will say.

Read more about Mr Obama's speech here. Speaker after speaker during the opening two nights of the convention have hammered Mr Trump, saying he has "quit" on the United States with a disinterested coronavirus response and a presidency geared solely for his conservative political base.