U.S. President Donald Trump is facing pressure to cooperate with President-elect Joe Biden's team to ensure a smooth transfer of power when the new administration takes office in January.

The General Services Administration is tasked with formally recognizing Biden as president-elect, which begins the transition. But the agency's Trump-appointed administrator, Emily Murphy, has not started the process and has given no guidance on when she will do so.

That lack of clarity is fueling questions about whether Trump, who has not publicly recognized Biden's victory and has falsely claimed the election was stolen, will impede Democrats as they try to establish a government.

There is little precedent in the modern era of a president erecting such hurdles for his successor. The stakes are especially high this year because Biden will take office amid a raging pandemic, which will require a comprehensive government response.

"America’s national security and economic interests depend on the federal government signaling clearly and swiftly that the United States government will respect the will of the American people and engage in a smooth and peaceful transfer of power," Jen Psaki, a Biden transition aide, tweeted Sunday.

The advisory board of the nonpartisan Center for Presidential Transition also urged the Trump administration to "immediately begin the post-election transition process and the Biden team to take full advantage of the resources available under the Presidential Transition Act."

Biden, who was elected the 46th president on Saturday, is taking steps to build a government despite questions about whether Trump will offer the traditional assistance.

He is focusing first on the virus, which has already killed nearly 240,000 people in the U.S. Biden on Monday announced details of a task force that will create a blueprint to attempt to bring the pandemic under control that he plans to begin implementing after assuming the presidency on Jan. 20.

Former Surgeon General Dr. Vivek Murthy, ex-Food and Drug Administration (FDA) Commissioner Dr. David Kessler and Dr. Marcella Nunez-Smith, a Yale University associated professor and associate dean whose research focuses on promoting health care equality for marginalized populations, are its co-chairs.

Biden pledged in remarks Monday to work with "governors and local leaders of both parties" to craft a response to the coronavirus pandemic and called on Americans to "put aside the partisanship and the rhetoric that’s designed to demonize one another" and come together to fight the virus.

"It’s time to end the politicization of basic responsible public health steps, like mask wearing, social distancing," he said. "We have to come together to heal the soul of this country so that we can effectively address this crisis as one country, where hardworking Americans have each other’s backs, and we’re united in our shared goal: defeating this virus."

In his statement announcing the task force, Biden said that tackling the pandemic is "one of the most important battles our administration will face, and I will be informed by science and by experts."

"The advisory board will help shape my approach to managing the surge in reported infections; ensuring vaccines are safe, effective and distributed efficiently, equitably and free; and protecting at-risk populations," he said.

There are also 10 members, including two former Trump administration officials: Rick Bright, who said he was ousted as head of the Biomedical Advanced Research and Development Authority after criticizing the federal government's response to the coronavirus, and Luciana Borio, who until last year was a biodefense specialist on the National Security Council.

The remainder of the panel includes experts with expertise in a number of areas, including Eric Goosby, who was former President Barack Obama's global AIDS coordinator.

Biden was also launching agency review teams, groups of transition staffers that have access to key agencies in the current administration. They will collect and review information such as budgetary and staffing decisions, pending regulations and other work in progress from current Trump administration staff at the departments to help Biden’s team prepare to transition.

But that process can't begin in full until the GSA recognizes Biden as president-elect. The definition of what constitutes a clear election winner for the GSA is legally murky, making the next steps unclear, especially in the short term.

The GSA's leadership is supposed to act independently and in a nonpartisan manner, and at least some elements of the federal government already have begun implementing transition plans. Aviation officials, for instance, have restricted the airspace over Biden's lakefront home in Wilmington, Delaware, while the Secret Service has begun using agents from its presidential protective detail for the president-elect and his family.

George W. Bush, the only living Republican former president, called Biden "a good man, who has won his opportunity to lead and unify our country."

But other Republicans, including Sen. Lindsey Graham of South Carolina, urged Trump to continue pursuing legal challenges related to the election, making a bumpy transition more likely.

Transition planning also may hinge on two Senate races in Georgia that have advanced to a Jan. 5 runoff. If Republicans hold those seats, they'll likely retain the Senate majority and be in a position to slow confirmation of Biden's top Cabinet choices and complicate his legislative goals, including calls for expanding access to health care and bolstering the post-pandemic economy with green jobs and infrastructure designed to combat climate change.

That could test Biden's campaign pledge to move past the divisiveness of the Trump era and govern in a bipartisan manner.

While Biden's aides acknowledged it would be easier for him to get his proposals enacted with Democrats controlling the Senate, Stef Feldman, the policy director on his campaign, said Biden has been known for working with Republicans to move legislation.

"The president-elect’s plan will remain the president-elect’s plans regardless of who wins the Senate majority, and he will work with colleagues across the aisle in order to get it done," she said.

Those close to Biden say he will navigate the period ahead by harnessing his sense of empathy that became a trademark of his campaign. Biden often spoke of the pain he experienced following the deaths of his first wife and young daughter in a 1972 car crash, and son Beau's 2015 death from brain cancer.

"My brother knows how to feel," said Valerie Biden Owens, Biden's sister and longtime top adviser. "Joe’s strength has been resilience and recovery, and that’s what we need as a country."