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.

After an expanded detention facility for child migrants reopened in Carrizo Springs, Texas, Rep. Alexandria Ocasio-Cortez, D-N.Y., tweeted Tuesday, “This is not okay, never has been okay, never will be okay - no matter the administration or party.”

In a press briefing Wednesday, Psaki attempted to cast the Biden administration’s efforts to manage immigration as a major improvement over President Donald Trump’s policies but didn’t fully address Ocasio-Cortez's criticism that such facilities shouldn’t exist at all.

Psaki said the administration had three options when it comes to child migrants: to send them back to their countries (which she said can be dangerous), to transfer them to a facility managed by the Department of Health and Human Services, or to put them in the care of families or sponsors "without any vetting." She said the administration has chosen the middle option.

“What we are doing is working as quickly as possible to process these kids into these HHS facilities, which have been revamped, which have medical and educational services available, so that we can then transfer them to families. That's what our approach is,” Psaki said.

Psaki would not commit to a request to allow media in to prove that children are treated humanely, citing privacy and security concerns. Psaki tried to explain the administration’s options in dealing with minors at the border and why the detention facilities have become a primary strategy.

“This is a difficult situation. It's a difficult choice. That's the choice we've made,” she said.

Psaki also attempted to defend delays in transferring children from facilities run by Customs and Border Protection, which often lack amenities, to Health and Human Service facilities that are intended for longer-term care. By law, children are supposed to spend no more than 72 hours in Customs and Border Protection facilities after initial apprehension.

“There were some delays last week because of weather, and because some of these facilities to safely move these kids to, did not have power and were not in a place where they could -- they had the capacity to take in these kids and do it safely. That is not our objective. That is not our goal," Psaki said. "So some, unfortunately, did stay four days, five days, or longer, but the objective is to move them as quickly as possible to the HHS sponsored facilities.”

-ABC News' Sarah Kolinovsky