WHITE HOUSE - U.S. President Donald Trump and former Vice President Joe Biden traded verbal attacks about COVID-19 vaccines in their respective Labor Day remarks.

The president called for the Democratic Party nominees, Biden and running mate U.S. Senator from California Kamala Harris, to "immediately apologize for the reckless anti-vaccine rhetoric."

Trump, Biden Clash Over COVID-19 Vaccine Rhetoric

Biden told reporters in Pennsylvania on Monday that he would like to see a vaccine tomorrow, even if it cost him the election. But "if we do have a really good vaccine, people are going to be reluctant to take it" because the president’s repeated misstatements and falsehoods with respect to the virus are "undermining public confidence."

Trump, Biden Clash Over COVID-19 Vaccine Rhetoric

"Nothing he has told us so far has been true," Biden later said during a virtual campaign event with the AFL-CIO, an umbrella federation for U.S. labor unions.

Trump, Biden Clash Over COVID-19 Vaccine Rhetoric

Trump, holding his first news conference on the North Portico of the White House, said that contrary to “political lies,” any vaccine approved for mass inoculation by the federal government will be “very safe and very effective.”

The Republican and Democratic party nominees made their remarks as the presidential campaign turned to the homestretch on the annual Labor Day holiday – a time when COVID-19, the disease caused by the coronavirus, is still killing about 1,000 Americans every day, according to data from the Centers for Disease Control and Prevention.

Biden went Monday to the key political battleground state of Pennsylvania in the eastern U.S. for the AFL-CIO event, appearing with the organization’s president, Richard Trumka.

"He's downright un-American," Biden said of Trump, accusing the president of hesitating to act to minimize the public health and economic ramifications of the pandemic because it would have lowered stock market prices, hurting the president's corporate interests and those of his friends.

"He lives by a code of greed, lies and selfishness," added Biden on the video link with the labor boss.

Trump, in contrast, hailed his administration’s performance amid the pandemic, predicting a swift, “Super-V” recovery for the U.S. economy and predicting that if Biden, whom he called “a stupid person,” wins the election, “China will own this country.”

Trump has portrayed himself as standing up to China on trade issues and criticizing that country for allowing the coronavirus to spread globally, wrecking America’s economic recovery.

The U.S. jobless rate dipped to 8.4% in August, but economic experts say it could take months for a more robust recovery to take hold. Only about half the 22 million jobs that were lost in the pandemic have been recovered, with many employers paring their payrolls even as they have reopened their businesses.

Biden is collecting endorsements from three organized labor groups: The Laborers' International Union of North America, the International Union of Elevator Constructors and the National Federation of Federal Employees.

Collectively, the three unions represent hundreds of thousands of workers nationwide that the Biden campaign hopes to mobilize for support.

Trump has emphasized his endorsement from unions representing police officers, stressing a “law and order” message amid peaceful urban demonstrations and some violence at protests in response to the deaths of Blacks by police in numerous cities.

Trump is also fighting to maintain support among veterans and those serving in the U.S. military after a magazine, citing four unnamed people, reported that he had referred to Marines buried in an American cemetery near Paris as "losers" and "suckers" and declined to visit their graves during a 2018 trip to France.

“Only an animal would say that,” Trump replied when asked about The Atlantic’s article during Monday’s news conference. He termed the article a “phony story” that others have refuted.

Several news organizations, including Fox News, which is generally sympathetic to Trump, have confirmed elements of the story, attributed to their own sources, which they have not named.

Biden, earlier Monday, met with three union workers who had served in the U.S. military at a home in Lancaster, Pennsylvania.

“Do you think most of those guys and women are suckers?” Biden asked.

Meanwhile, Harris and Vice President Mike Pence both visited the highly contested battleground state of Wisconsin in the Midwest on Monday.