With less than two weeks left for the close of polling, Barack Obama hit the campaign trail on Wednesday in support of Democratic White House hopeful Joe Biden, launching with a blistering attack on US President Donald Trump.

The former US president slammed Trump for his handling of the Covid-19 pandemic, his secret bank account in China, his tweeting, and for “making things up”. Obama urged Democrats to vote like never before to “leave no doubt” about the outcome.

Obama’s drive-in rally in Philadelphia where he canvassed for his former vice-president was the largest turnout yet for a Biden campaign event.

Biden was off the campaign trail on Wednesday to prepare for the final presidential debate with his rival on Thursday, to be held in Nashville, Tennessee.

President Trump, too, was out campaigning, visiting North Carolina, a key battleground state, keeping up with his one-rally-a-day routine.

Targeting Trump, former president Obama said, “Eight months into this pandemic, cases are rising again across this country. Donald Trump isn’t suddenly going to protect all of us. He can’t even take the basic steps to protect himself.” It was a reference to the US president himself contracting Covid-19.

“We literally left this White House a pandemic playbook… they probably used it to prop up a wobbly table somewhere,” Obama said.

Obama criticised the Trump administration for driving a booming economy into the ground, giving tax breaks to billionaires, trying to gut the affordable health care system in the middle of a pandemic, and leaving America’s standing abroad in tatters.

“His TV ratings are down. So, you know that upsets him. But the thing is, this is not a reality show. This is reality,” Obama said. “The rest of us have to live with the consequences of him proving himself incapable of taking the job seriously.”

On recent reports of Trump’s bank account in China, Obama said, “He’s got a secret Chinese bank account. How is that possible? Can you imagine if I had had a secret Chinese bank account when I was running for re-election? You think Fox News might have been a little concerned about that. They would have called me Beijing Barry.”

The former president, who remains very popular in the Democratic Party, was on a mission to energise Democrats to vote, especially young Black and Hispanic Americans – who so far don’t appear to be excited about Biden – and those who are likely to stay home on Election Day.

“We can’t be complacent. I don’t care about the polls,” Obama said, referring to a slew of opinion polls that have Biden in the lead nationally and in battleground states, as was Hillary Clinton, the Democratic candidate, in 2016. “There were a whole bunch of polls last time. Didn’t work out. Because a whole bunch of folks stayed at home. And got lazy and complacent. Not this time. Not this election.”

Urged Democrats to go out and vote, Obama said, “We’ve got to turn out like never before. We cannot leave any doubt in this election.”

Later in the day, national security officials warned of possible interference in the US election by Russia and Iran in general, after letters were purportedly sent out in the name of a white supremacist group, “Proud Boys”, to some Democrats in Florida and Alaska, threatening them to vote for Trump or face consequences.