Antony Blinken has been officially sworn in as secretary of state by a senior career ambassador, Carol Perez, who is currently serving as acting Under Secretary for Management.

He also has launched his official Twitter account -- @SecBlinken -- and tweeted some photos from the ceremony, which was closed to journalists.

-ABC News' Conor Finnegan

Biden, in afternoon remarks from the White House, announced that his administration has secured commitments from coronavirus vaccine makers to buy another 200 million doses to arrive this summer, raising the total to 600 million and ensuring the U.S. will eventually have two shots of the Pfizer and Moderna vaccines for nearly every American.

Biden also told the nation to expect a modest uptick in production in the near term -- from 8.6 million doses a week to a minimum of 10 million a week -- for the next three weeks.

"This is going to allow millions of more Americans to get vaccinated sooner than previously anticipated. We've got a long way to go, though," Biden said.

The announcement does not resolve the major shortages the nation is experiencing now, and does not suggest the Biden administration has found a novel way to ramp up production quickly.

One Biden administration official, who briefed reporters earlier on condition of anonymity, did not provide a firm timetable on the 200 million extra doses, pointing to the summer, but hailed the move as a guarantee that every American who wants a shot can get one.

Biden said it was enough to vaccinate 300 million Americans "by end of the summer, beginning of the fall."

-ABC News' Anne Flaherty

The state of Texas has won a nationwide temporary restraining order against one of Biden's first executive actions as president -- a 100-day pause of immigrant deportations.

A federal district court judge says status quo enforcement operations can continue for at least the next 14 days while both sides present their case, after which an extended injunction against the policy could be issued or the restraining order lifted.

Biden's DHS released a "Day One" memorandum on Jan. 20 establishing a moratorium on enforcement actions against most immigrants.

The Texas lawsuit signals the beginning of an expected wave of court challenges by Republicans targeting Biden policies after years of watching Democrats use the courts to hobble Trump's moves.

-ABC News Senior Washington Reporter Devin Dwyer

After 45 Republicans sided with his effort to dimisss the impeachment trial of former President Donald Trump for being unconstitutional, Republican Kentucky Sen. Rand Paul expressed excitement about the vote count for his failed effort.

"We're excited about it. It's one of the few times in Washington where loss is actually a victory," Paul said to reporters on Capitol Hill. "And 45 votes means that the impeachment trial is dead on arrival."

If the final vote on conviction falls at 55-45, the Senate would be 12 votes short of what is necessary to convict Trump. In order to convict Trump by the necessary two-thirds majority, at least 17 Republican senators would need to join all 50 Democrats.

Even with Tuesday's vote, there is no guarantee that the trial proceedings will not sway the votes of some senators.

Shortly after the vote, the Senate adjourned the trial until Feb. 9.

-ABC News' Allison Pecorin