WILMINGTON, Del. — President-elect Joe Biden’s first Cabinet picks are coming Tuesday and planning is underway for a pandemic-modified inauguration in January as his team moves forward despite roadblocks from the Trump administration.

Ron Klain, Biden’s incoming chief of staff, offered no details Sunday about which department heads Biden would first announce. The Associated Press has reported that Biden could name his nominee for secretary of state or treasury secretary this coming week.

Biden has pledged to build the most diverse government in modern history, and he and his team often speak about their desire for his administration to reflect America. He is being watched to see whether he will make history by nominating the first woman to lead the Pentagon, the Treasury Department or the Department of Veterans Affairs, or the first African American at the top of the Defense Department, the Interior Department or the Treasury Department.

Biden said last week he had settled on his pick for treasury secretary.

Klain said the Trump administration’s refusal to clear the way for Biden’s team to have access to key information about agencies and federal dollars for the transition is taking its toll on planning, including the Cabinet selection process. Trump’s General Services Administration has yet to acknowledge that Biden won the election — a determination that would remove those roadblocks.

“We’re not in a position to get background checks on Cabinet nominees. And so there are definite impacts. Those impacts escalate every day,” Klain told ABC’s “This Week.”

Even some Republicans have broken with Trump in recent days and called on him to accept the results of the election.

“I, frankly, do think it’s time to — well, it was past time to start a transition, to at least cooperate with the transition,” said Sen. Kevin Cramer, R-N.D., on NBC’s “Meet the Press.” He said the GSA’s designation should happen Monday “because it didn’t happen last Monday morning,” to give the incoming administration “all the time they need.”

Sen. Lamar Alexander, R-Tenn., said there was a “very good chance” Biden would be president and that Biden and his team should have access to relevant information for the transition. After a federal judge’s ruling against the Trump campaign in an election challenge in Pennsylvania on Saturday, GOP Sen. Pat Toomey of Pennsylvania said the president had “exhausted all plausible legal options” and Toomey congratulated Biden on his win.

Sen. Lisa Murkowski, R-Alaska, said in a statement Sunday that courts had so far found Trump’s claims to be without merit and called a “pressure campaign” on state legislators to influence the electoral outcome unprecedented and inconsistent with the democratic process. “It is time to begin the full and formal transition process,” she said.

Also Sunday, former Republican Gov. Chris Christie of New Jersey, a longtime Trump supporter, said on ABC that it was time for the president to stop contesting the outcome. Christie said Trump’s legal team was a “national embarrassment.”