Former US President Barack Obama on Wednesday ripped incumbent President Donald Trump as he appeared at his first public rally for his former Vice President, Joe Biden, ahead of the November 3 presidential election.

"This is not a reality show. This is reality," said Obama at the rally which took place in Philadelphia, in the battleground state of Pennsylvania.

"And the rest of us have had to live with the consequences of him proving himself incapable of taking the job seriously," he charged.

“We cannot afford four more years of this, Philadelphia,” Obama warned, adding that “the next 13 days will matter for decades to come” and urging Americans to go out and vote.

Obama ripped Trump’s response to the COVID-19, saying “the idea that this White House has done anything but screw this up is just untrue."

“We literally left this White House a pandemic playbook,” Obama said. “They probably used it to, I don’t know, prop up a wobbly table somewhere.”

Obama wondered how Trump could be trusted to lead the country through the pandemic if he couldn’t take the “basic steps” to take care of himself, referencing Trump’s aversion to wearing a mask and his recent bout with COVID-19.

“The economic damage he inflicted by botching the pandemic response means he will be the first president since Herbert Hoover to lose jobs,” he claimed, while also condemning Republican plans to cancel the Affordable Care Act, also known as Obamacare, amid the pandemic.

“It’s shameful. The idea that you would take health care away from people at the moment they need it the most—what is the logic of that? There is no logic,” he said.

"They keep on promising we're going to have a great replacement. They said it's coming. It's been coming in two weeks for the last 10 years. Where is it? Where is this great plan to replace Obamacare? They've had 10 years to do it. There is no plan. They've never had one,” added Obama.