Biden to tap Yellen as first woman Treasury sec.

U.S. President-elect Joe Biden forged ahead Monday with his picks for key positions in the next administration - bringing back some familiar faces… and potentially making history.

Sources told Reuters Biden plans to nominate former Federal Reserve Chairwoman Janet Yellen as his Treasury secretary. She would be the first woman to ever hold the position and be charged with leading a battered U.S. economy back to steady growth.

REPORTER: "Why'd you go with national security first?"

BIDEN: "Cuz it's national security."

Biden, who has vowed to undo President Donald Trump's "America First" policies, also tapped Antony Blinken for secretary of state. A longtime trusted aide of the former vice president, Blinken has held senior foreign policy positions in the last two Democratic administrations.

Biden also wants Jake Sullivan as his next national security adviser and Linda Thomas-Greenfield as U.S. Ambassador to the United Nations - two expected nominees with high-level government experience.

For the Department of Homeland Security - Biden chose lawyer Alejandro Mayorkas, entrusting the Cuban-American immigrant to help reverse Trump's hardline immigration policies.

Asked by a reporter in Wilmington, Delaware if he expects any roadblocks from Republicans in Congress during the confirmation process for his nominees, Biden responded with a laugh…

"Are you kidding me?"

In another sign that his administration will prioritize the problem of climate change, Biden announced that John Kerry, President Obama's former U.S. secretary of state, would become his special envoy for climate.

Biden is assembling an administration as he prepares to be sworn in on Jan. 20 to lead a country facing its greatest public health crisis in living memory, even as President Trump refuses to concede and is blocking the government from providing the support normally given to a president-elect.