WASHINGTON, July 24 — Democratic presidential candidate Joe Biden and former President Barack Obama blasted Republican President Donald Trump's handling of the coronavirus pandemic in a video aired yesterday, as the Biden campaign tapped the star power of America's first Black president.

Biden, who was vice president in the Obama administration, sat down facing the former president in a chair across a room for a "socially distanced” conversation.

Both men released the video on Twitter, where Obama has 120.8 million followers, the most on the platform.

"Can you imagine standing up when you were president, saying, 'It's not my responsibility?'” Biden asked Obama, referring to Trump's efforts to evade criticism for the pandemic response.

"Those words didn't come out of our mouths when we were in office,” Obama replied.

In response, Trump attacked Obama and Biden on Twitter.

"Remember, I wouldn't even be here if it weren't for them,” he wrote yesterday. "They did a terrible job!”

With traditional campaigning still in limbo due to the pandemic, the video offered a glimpse of how Obama — still overwhelmingly popular among Democratic voters — may be deployed to build enthusiasm for November's presidential election.

During their first in-person meeting since Biden became presumptive Democratic nominee, they spoke about the need to expand on the Affordable Care Act, also known as "Obamacare,” their administration's signature programme that vastly expanded US healthcare coverage.

The Trump administration has petitioned the US Supreme Court to invalidate the ACA.

"It is hard to fathom anybody wanting to take away people's health care in the middle of a major public health crisis,” Obama said.

They also discussed Biden's ability to empathise, a trait his campaign has stressed to contrast him with Trump.

"I don't understand his inability to get a sense of what people are going through,” Biden said. "He can't relate in any way.”

Obama said, "It is a sign of leadership when you are willing to hear other people's experiences.” — Reuters