President-elect Joe Biden has decided on a Treasury secretary nominee and said he'll make the announcement around Thanksgiving - calling his choice "someone who I think will be accepted by all elements of the Democratic Party."

But Biden also took aim at President Trump for refusing to concede the presidential election, while taking questions from reporters Tuesday after he and Vice President-elect Kamala Harris held a virtual meeting with a bipartisan group of governors. He accused Trump of stalling the transition between administrations.

The president is being "totally irresponsible" and is sending an "incredibly damaging message" to the rest of the world, Biden said.

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Asked about the president's invitation for a meeting with Republican legislative leaders from Michigan at the White House, Biden emphasized, "we won Michigan. It's going to be certified."

Trump is trying to reverse Biden's projected victories in that state and other key battleground. Biden stressed, "it's outrageous what he's doing."

President-elect Joe Biden and Vice President-elect Kamala Harris participate in a meeting with the National Governors Association's executive committee at The Queen theater, Nov. 19, in Wilmington, Del. (AP Photo/Andrew Harnik)

President-elect Joe Biden and Vice President-elect Kamala Harris participate in a meeting with the National Governors Association's executive committee at The Queen theater, Nov. 19, in Wilmington, Del. (AP Photo/Andrew Harnik)

The Biden-Harris meeting with the governors focused on the battle to combat the coronavirus pandemic, which has surged again across the nation in recent weeks with spike in new cases. The nation passed a grim milestone on Wednesday: topping a quarter of a million deaths from COVID-19 since the pandemic swept the country in February and March.

Biden said that an "implementation of a national mask mandate" was discussed. "It's not a political statement. It's a patriotic duty."

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The meeting took place soon after Republican Gov. Chris Sununu of New Hampshire became the latest governor to issue a mask mandate. New Hampshire became the 37th state to implement such a mandate.

The president-elect also reaffirmed that "I am not going to shut down the economy. Period. I'm going to shut down the virus. That's what I'm going to shut down. I'll say it again - no national shutdown. No national shutdown." He added that shutting down the economy "would be counterproductive."

Fox News' Tara Prindiville and Madeleine Rivera contributed to this report