U.S. President-elect Joe Biden speaks on Nov. 19, 2020, in Wilmington, Delaware. (PHOTO NOT FOR SALE)(Getty/Kyodo)

U.S. President-elect Joe Biden said Monday he will nominate his longtime adviser Antony Blinken as secretary of state along with other veterans to join his national security team, underscoring his resolve to place greater emphasis on multilateralism and alliances in foreign policy.

As the 78-year-old Democrat steps up his preparation to take office in January, Republican President Donald Trump finally gave the green light to start the transition process while continuing his legal fight and other efforts to overturn the results of the Nov. 3 election.

The move means that the incoming administration will gain access to funds, intelligence briefings and other resources necessary for a smooth transfer of power.

Biden's foreign and national security team will be joined by former Secretary of State John Kerry, who was tapped as special presidential envoy for climate change issues, set to be a key focus of the Biden administration.

Jake Sullivan, another policy adviser to Biden and a former director of policy planning at the State Department, was selected as national security adviser, while Linda Thomas-Greenfield, a black woman and a former assistant secretary of state for African affairs, is eyed for the post of ambassador to the United Nations.

The team is expected to work to bring about sweeping changes from Trump's "America First" agenda, which has pulled the United States out of international commitments and agreements, including the Paris climate accord, while questioning the value of traditional alliances.

"I need a team ready on day one to help me reclaim America's seat at the head of the table, rally the world to meet the biggest challenges we face, and advance our security, prosperity, and values," Biden, the former vice president who served under Trump's predecessor Barack Obama, said in a statement.

"These individuals are equally as experienced and crisis-tested as they are innovative and imaginative...they also reflect the idea that we cannot meet the profound challenges of this new moment with old thinking and unchanged habits -- or without diversity of background and perspective," he added.

Antony Blinken. (Kyodo)  

Other nominees announced Monday were Avril Haines, who will seek to become the first woman to serve as the director of national intelligence, and Cuban-born Alejandro Mayorkas, set to become the first Latino and first immigrant nominated to serve as secretary of homeland security.

As for the next treasury secretary, Biden plans to nominate former Federal Reserve chairwoman Janet Yellen, making her potentially the first woman to hold the job, according to U.S. media.

The heads of executive departments and some other high-ranking officials require Senate approval.

Blinken, who has advised Biden on foreign policy since 2002, was deputy secretary of state and deputy national security adviser under the Obama-Biden administration that lasted for eight years from January 2009.

The 58-year-old has been a vocal critic of Trump's foreign policy, slamming it as having weakened U.S. alliances and left a vacuum in the world for China to fill. He has called for the importance of working with U.S. partners so that the United States can engage with China from "a position of strength."

Both Blinken and Sullivan played a part in the Obama-Biden administration's foreign policy including the Asia-Pacific "rebalance" strategy, a phrase used to signal a focus on the region amid China's emergence as an influential regional power, according to Biden's transition team.

Kerry, 76, who was secretary of state between 2013 and 2017, was a key architect of the Paris accord, which Biden has pledged to rejoin immediately after he takes office.

Janet Yellen. (Getty/Kyodo)

As a special presidential envoy, Kerry will sit on the National Security Council, marking the first time that the NSC will include an official dedicated to climate change, reflecting Biden's commitment to addressing what he considers an urgent national security issue, his transition team said.

Biden has not announced his defense secretary pick. Michele Flournoy, a former undersecretary of defense for policy, has been among the names floated to serve in the post.

Trump, after refusing to concede defeat for more than two weeks after Biden was projected winner in the presidential election, admitted Monday that authorizing the start of the transition process serves the "best interest" of the country.

But the 74-year-old incumbent suggested that he has no intention to backtrack from his unsubstantiated claim that the election was rigged against him, saying in a pair of tweets, "Our case STRONGLY continues, we will keep up the good...fight, and I believe we will prevail!"