President-elect Joe Biden speaks Monday in Wilmington, Del., during a virtual meeting with the U.S. Conference of Mayors.

WILMINGTON, DE – NOVEMBER 23:  President-elect Joe Biden speaks during a virtual meeting with the United States Conference of Mayors on November 23, 2020 in Wilmington, Delaware. As President-elect Biden waits to be approved for official national security briefings, the names of top members of his national security team are being announced to the public. Calls continue for President Trump to concede the election and let the transition proceed without further delay. (Photo by Mark Makela/Getty Images)