Emily Murphy, the administrator of the General Services Administration, on Monday formally designated Joseph R. Biden Jr. as the apparent winner of the presidential election, providing federal funds and resources to begin a transition and authorizing his advisers to begin coordinating with Trump administration officials.
The decision came after several more senior Republican lawmakers denounced Ms. Murphy’s delay in allowing the peaceful transfer of power to begin, a delay that Mr. Biden and his top aides said was threatening national security and the ability of the incoming administration to effectively plan for combating the ongoing pandemic.
In her letter, Ms. Murphy said she was “never directly or indirectly pressured by any executive branch official — including those who work at the White House or the G.S.A.” She defended her delay by saying that she did not want to get ahead of the constitutional process of counting votes and picking a president.
“I do not think that an agency charged with improving federal procurement and property management should place itself above the constitutionally-based election process,” she wrote in a letter to Mr. Biden’s transition.
President Trump, who has spent more than two weeks claiming falsely that he won the election and pushing conspiracy theories about fraudulent voting, said on Twitter that he accepted Ms. Murphy’s decision even as he vowed to continue legal fights challenging the result.
“Our case STRONGLY continues, we will keep up the good fight, and I believe we will prevail!” Mr. Trump wrote. “Nevertheless, in the best interest of our Country, I am recommending that Emily and her team do what needs to be done with regard to initial protocols, and have told my team to do the same.”
Ms. Murphy refuted Mr. Trump’s assertion that he directed her to make the decision, saying in her letter that “I came to my decision independently, based on the law and available facts.”
In her letter, Ms. Murphy said she made her decision on Monday because of “recent developments involving legal challenges and certifications of election results,” likely referring to the certification of votes by election officials in several states and a string of court decisions that have rejected Mr. Trump’s challenges.
Michigan’s statewide electoral board approved its presidential vote tally on Monday, resisting pressure from Mr. Trump to delay the process and paving the way for Mr. Biden to receive the state’s 16 electoral votes. In Pennsylvania, the State Supreme Court ruled against the Trump campaign and Republican allies, stating that roughly 8,000 ballots with signature or date issues must be counted.
Most of Mr. Trump’s Republican allies had stood by his side as he attempted to overturn Mr. Biden’s victory. But on Monday, some of the Senate’s most senior Republicans sharply urged Ms. Murphy to allow the transition to proceed.
Senator Lamar Alexander of Tennessee, a senior Republican who is retiring this year, issued his second call in the last three days for a prompt transition.
“Since it seems apparent that Joe Biden will be the president-elect, my hope is that President Trump will take pride in his considerable accomplishments, put the country first and have a prompt and orderly transition to help the new administration succeed,” said Mr. Alexander, a close friend of Senator Mitch McConnell, Republican of Kentucky and the majority leader. “When you are in public life, people remember the last thing you do.”
Earlier in the day, Senators Rob Portman of Ohio and Shelley Moore Capito of West Virginia released statements breaking from Mr. Trump and calling for Mr. Biden to begin receiving coronavirus and national security briefings.
