White House press secretary Jen Psaki used the phrase "crisis on the border" during the briefing on Thursday -- a notable choice of words after the administration has avoided describing the situation that way.

She later seemed to walk it back when reporters asked if her phrasing was indicative of a change in how the White House viewed the situation. She reverted back to using the phrase "challenges at the border" and maintained there is no change in administration messaging.

THE WORD THE BIDEN ADMINISTRATION WON'T USE WHEN DESCRIBING THE BORDER? CRISIS

During the White House press briefing Thursday, Psaki was asked about lending doses of AstraZeneca COVID-19 vaccine to Mexico and Canada.

"I can confirm that we have 7 million releasable doses available of AstraZeneca," Psaki said, adding that "2.5 million of those, we are working to finalize plans to lend those to Mexico and 1.5 million to Canada."

During a back-and-forth about vaccine doses, Psaki said that there have been "expectations set outside of, unrelated to any vaccine doses or requests for them, that they would be partners in dealing with the crisis at the border.

"And there have been many requests unrelated that they, for doses of these vaccines…every relationship has multiple layers," Psaki said, adding that there "is rarely just one issue" when working with other countries. "Certainly that’s not the case with Mexico or any country around the world."

Psaki was then asked whether she meant to call it a "crisis at the border."

She quickly replied: "Challenges at the border."

When asked whether her comments reflected shift in administration messaging regarding the situation at the border, she said: "Nope."

The U.S. is facing what the Biden Administration admits is an "overwhelming" number of migrants at the southern border while scrambling to construct new facilities to hold child migrants -- but it is doggedly refusing to describe the situation as a "crisis."

"It doesn’t matter what you call it. It is an enormous challenge," Psaki said last week, before saying: "We don’t feel the need to, you know, play games with what it’s called."

While numbers have been increasing at the border for months, particularly of unaccompanied children (UACs) and family units, they have spiked since President Biden took office. The number of UACs in custody has tripled in recent weeks, while there were more than 100,000 migrant encounters in February.

Psaki said last week about a "crisis": "I don't think we need to sit here and put new labels on what we have already conveyed is challenging, what we have conveyed is a top priority for the president."

And earlier this month, Biden said "no" when asked about a crisis.

So far in 2021, the numbers have been higher than in 2019, indicating the crisis or "challenge" could be significantly greater this year, and the administration has made moves to indicate it recognizes that. It has opened up migrant centers to deal both with family units and UACs and has looked at a Virginia military base and other sites to house child migrants.

And while not calling it a crisis, officials have still been sounding the alarm about the situation.

"We continue to struggle with the number of individuals in our custody, especially in a pandemic," Acting CBP Commissioner Troy Miller said this week as he announced border numbers.

Department of Homeland Security Secretary Alejandro Mayorkas, who has flat-out denied there was a crisis, last week emailed DHS staff urging them to volunteer to help CBP at the border amid what he described as "overwhelming" numbers.

"Today, I activated the Volunteer Force to support Customs and Border Protection (CBP) as they face a surge in migration along the Southwest Border," Mayorkas said in an email to staff, seen by Fox News.

"You have likely seen the news about the overwhelming numbers of migrants seeking access to this country along the Southwest Border," he said. "President Biden and I are committed to ensuring our Nation has a safe, orderly, and humane immigration system while continuing to balance all of the other critical DHS missions."

Fox News' Adam Shaw and Griff Jenkins contributed to this report.