Former U.S. President Barack Obama on Tuesday harshly criticized President Donald Trump's response to the coronavirus pandemic and faulted him for turning the White House into a "hot zone."

"More than 225,000 people in this country are dead. More than 100,000 small businesses have closed. Half a million jobs are gone in Florida alone. Think about that," Obama said, speaking from Orlando as he campaigned for Democratic nominee Joe Biden.

He continued, "And what's his closing argument? That people are too focused on Covid. He said this at one of his rallies. COVID, COVID, COVID, he's complaining. He's jealous of COVID's media coverage. If he had been focused on COVID from the beginning, cases wouldn't be reaching new record highs across the country this week."

Obama, an important surrogate for Biden, campaigned for his former vice president for the second time in four days in Florida. The key battleground state could play a decisive role in the outcome of the election, and recent polls show a tight race between Trump and Biden.

Obama's Orlando speech built on a blistering rebuke of Trump he delivered last week in Pennsylvania, his first foray onto the campaign trail since a speech to the Democratic National Convention earlier in the year, and over the weekend in Florida.

Obama's speeches have shown how he is keeping tabs on the day-to-day news about Trump, and how the Biden campaign is deploying him to deliver some of its harshest attacks on the current President and his administration.

Former presidents usually avoid directly attacking their successor in the White House, but Obama has delivered full-throated criticisms of Trump while campaigning for Biden. But Trump, with the way he has continually attacked Obama, even suggesting he should be indicted, has changed the calculus, thrusting the former president onto the campaign trail.

Democrats hope Obama can help gin up enthusiasm among the Democratic base and encourage Black men, Latinos and younger voters in battleground states to turn out and vote.

He accused Trump of failing to take preventative measures to contain the virus across the nation and in the White House. He also pointed to the second recent outbreak among White House staff, which infected several aides including Vice President Mike Pence's chief of staff, Marc Short.

"Let me say this: I lived in the White House for a while," Obama said. "You know, it's a controlled environment. You can take some preventive measures in the White House to avoid getting sick. Except, this guy can't seem to do it. He's turned the White House into a hot zone."

Obama criticized the comments made over the weekend by White House chief of staff Mark Meadows, who told CNN's Jake Tapper on "State of the Union," "We are not going to control the pandemic. We are going to control the fact that we get vaccines, therapeutics and other mitigation areas."

"Listen, winter is coming," Obama said. "They're waving the white flag of surrender. Florida, we can't afford four more years of this." He added, "We cannot afford this kind of incompetence and disinterest."

The former president also criticized senior White House adviser Jared Kushner, Trump's son-in-law, for recent comments he made about Black Americans. Kushner said Monday on Fox News, "One thing we've seen in a lot of the Black community, which is mostly Democrat, is that President Trump's policies are the policies that can help people break out of the problems that they're complaining about. But he can't want them to be successful more than they want to be successful."

Obama seized on the comments, saying, "(Trump's) son-in-law says Black folks have to want to be successful. That's the problem." After a short pause, an incredulous-sounding Obama continued, "Who are these folks? What history books do they read? Who do they talk to?"

Trump responded to Obama's speech on Twitter, noting that the remarks were airing on Fox News and claiming his predecessor was drawing a small crowd and giving a "fake speech" for Biden.

"Listen, you've got a president right now, he wants full credit for an economy that he inherited, he wants zero blame for the pandemic he ignored. But you know what, the job doesn't work that way. You've got to be responsible 24/7. You've got to pay attention 24/7. Tweeting at the TV doesn't fix things. Watching TV all day doesn't fix things. Making stuff up doesn't fix things," Obama said.

One week from Election Day, Obama encouraged Floridians to vote early in-person or by mail. "Don't wait. Put it in the mail or drop it off at a dropbox location today. Don't take any chances, just get it done," Obama said.

"We have to turn out like never before, Orlando. We have to leave no doubt. We can't be complacent. We were complacent last time. Folks got a little lazy. Folks took things for granted. And look what happened. Not this time," Obama said.

Obama praised his former vice president, describing Biden as a man of "principle and character" and highlighting his empathy and decency.

"He made me a better president, and he's got the character and the experience to make us a better country," Obama said.

Obama laid out the ways Biden has said he would get the pandemic under control, including making coronavirus tests free and widely available, distributing a vaccine to every American at no cost and providing enough personal protective equipment to all front-line workers.

"He's going to make sure that small businesses that hold our communities together and employ millions of Americans can reopen safely, and he understands that we're not going to rebuild the economy and put people back to work until we get this pandemic under control," Obama said.

He lambasted Trump and Republicans for attempting to overhaul the Affordable Care Act, Obama's landmark health care plan.

"Last week, Trump flat out said he hopes the Supreme Court takes your health insurance away. Said it out loud," Obama said. "Don't boo, vote," he said, repeating a favorite line of his when the crowd booed. The Supreme Court is set to hear oral arguments on the future of the ACA, also known as Obamacare, next month.

Obama said if elected, Biden and his running mate Sen. Kamala Harris of California would "protect your health care, they will expand Medicare, they'll make insurance more affordable for everybody, because Joe knows that a president's first job is to keep us safe from all threats, foreign, domestic, and microscopic."