The U.S. Food and Drug Administration authorized use of a third COVID-19 vaccine in the U.S., declaring the Johnson & Johnson vaccine safe and effective in adults 18 and older.

ABC News Chief Anchor George Stephanopoulos asked Dr. Anthony Fauci about hesitancy from people over its reported efficacy compared to others.

"What do you say to those who want to wait for Moderna and Pfizr?" Stephanopoulos asked.

"We have to get away from that line of thought," Fauci responded. "We have three highly efficacious vaccines. Safe and efficacious."

"If I went into a clinic and said we have JJ now, I would take the one that is available to me now," Fauci continued.

The White House released a letter Saturday from President Biden to the speaker of the House and president pro tempore of the Senate on the airstrike in eastern Syria, in his effort to keep Congress "fully informed, consistent with the War Powers Act."

"I directed this military action consistent with my responsibility to protect United States citizens both at home and abroad and in furtherance of United States national security and foreign policy interests, pursuant to my constitutional authority to conduct United States foreign relations and as Commander in Chief and Chief Executive. The United States took this action pursuant to the United States' inherent right of self-defense as reflected in Article 51 of the United Nations Charter," Biden wrote in the letter.

This comes following some bipartisan criticism the White House received over the decision to carry out the airstrike in Syria.

-ABC News' Molly Nagle

As Biden departed the White House to board Marine One Saturday afternoon, he was asked if he planned to punish Saudi Arabia’s crown prince following a U.S. intelligence report that concluded he ordered the killing of journalist Jamal Khashoggi.

Biden carefully teased an announcement but said it wouldn’t specifically pertain to Khashoggi’s murder.

He said, “there will be an announcement on Monday as to what we’re going to be doing with Saudi Arabia in general.”

The president then left the White House for Delaware.

On Friday the Office of Director of National Intelligence released a highly anticipated report on the death of Khashoggi, a Washington Post columnist and Saudi dissident who was murdered and dismembered at the Saudi consulate in Istanbul in Oct. 2018.

It revealed the U.S. intelligence community found Saudi Arabia’s Crown Prince Muhammad bin Salman approved an operation to capture or kill him.

The Saudi government has denied that that the crown prince was involved and instead blamed the death on a rogue team of government agents.

The killing has roiled the United States' longstanding ties with Saudi Arabia.

Biden said he spoke to King Salman on Thursday, one day before the report was released.

In honor of Black History Month, NASA astronaut Victor Glover welcomed Harris to the International Space Station via virtual chat.

A pre-recorded video shared on Saturday by NASA, shows Harris and Glover discussing several topics, including the legacy of human spaceflight, observing Earth from the space station and prepping for missions from the Moon to Mars.

Glover is a long-duration crew member on the International Space Station and is responsible for spacecraft systems and performance.

The first day of hearings for Biden's pick for secretary of health and human services, Xavier Becerra, kicked off with glowing praise from Democrats, who heralded his experience, and criticism from Republicans, who think his resume is a detractor.

Both Sen. Patty Murray, D-Wash., and Sen. Diane Feinstein, D-Calif., who introduced Becerra, highlighted his potential to make history as the first Latino to lead the department and his experience leading massive departments and in policy as a congressman for 24 years. But Sen. Richard Burr, R-N.C., said he is “not sold” Becerra has the “necessary experience or skills to do this job at this moment.”

Becerra, in his opening statement, said he was committed to working in a bipartisan way.

“No one understands your states and communities better than you. We may not always agree, but if I’m fortunate enough to be confirmed, I will always listen to you and keep an open mind, find common cause, and work with you to improve the health and dignity of the American people,” Becerra said.

Becerra laid out his "vision" for the department with three goals: make COVID-19 treatments more accessible, bring down the cost of health care and restore faith in public institutions by putting science first.

-ABC News' Cheyenne Haslett