Donald Trump turned to fear tactics as he accused the left of trying to "destroy the American way of life" at rallies in Michigan and Wisconsin on Saturday.

The two Midwestern states were instrumental to the president's 2016 victory, and Trump packed in two rallies in the states. 

In back-to-back rallies, he accused the left of wanting to "erase American history" and "purge American values" warning that Democratic rival Joe Biden would put communities at risk.

READ MORE: US election polls: Donald Trump cuts Joe Biden's lead to nine points

Mr Trump offered his dark message as he faces headwinds not only in national polling, which shows Mr Biden leading, but also in key battleground surveys.

His comments come after his campaign, with far less cash than Mr Biden's, largely retreated from TV advertising in the Midwest, shifting much of its money to Sun Belt states such as Florida, North Carolina, Arizona and Georgia, as well as Pennsylvania.

As he tries to energise his base and keep on-the-fence voters from turning against him, Mr Trump sought to paint Democrats as "anti-American radicals" and said moderates had "a moral duty" to join the Republican Party.

"The Democrat Party you once knew doesn't exist," he said.

It was the same on issue after issue, as he claimed in hyperbolic terms Mr Biden's election would spur "the single biggest depression in the history of our country" and "turn Michigan into a refugee camp".

On the same day that Michigan reporting its highest number of new coronavirus cases in a single day, Trump also warned voters that Biden would "shut down the country, delay the vaccine and prolong the pandemic".

His message comes despite public health experts say the nation would be in far better shape had Mr Trump's administration taken more aggressive action early on.

In Michigan, he quipped that, in January, he "better damn well be president" while in Wisconsin, he wondered how he would process a loss.

"Can you imagine if I lose? I will have lost to the worst candidate in the history of American politics," he said. "What do I do?"

READ MORE: Donald Trump brands the government's top infectious disease expert as 'a Democrat' 

Mr Trump has continued to hold rallies despite the threat of the coronavirus, which put him in hospital for several days earlier this month.

Wisconsin broke the record for new positive virus cases on Friday - the third time that has happened in a week. The state also hit record highs for daily deaths and hospital admissions this past week.

Despite the growing numbers, audience members stood closely together in the cold, mostly without masks.

Mr Trump continued to call on Michigan governor Gretchen Whitmer to roll back restrictions that remain in place to try to halt the spread of the virus, prompting the crowd to break into a chant of "Lock her up".

The same chant broke out after he mentioned his 2016 Democratic rival Hillary Clinton and Minnesota Representative Ilhan Omar.

Mr Trump has an aggressive campaign schedule in the coming days, with rallies planned for Sunday in Nevada, Monday in Arizona and Tuesday in Pennsylvania.