Biden's 1st 100 days live updates: Senate passes COVID relief bill along party lines

In an exchange that clearly struck a nerve during a press briefing on Thursday, White House press secretary Jen Psaki flatly refused to give the Trump administration any credit for the vaccine rollout.

“I don't think anyone deserves credit when half a million people in the country have died of this pandemic,” Psaki said in response to ABC News Senior White House Correspondent Mary Bruce.

“What our focus is on, and what the president's focus is on when he came into office just over a month ago, was ensuring that we had enough vaccines. We have that -- we're going to have them now. We had enough vaccinators, and we had enough vaccine locations to get this pandemic under control. There's no question, and all data points to the fact that there were not enough of any of those things when he took office,” she said.

Bruce pressed Psaki on whether the Trump administration’s Operation Warp Speed deserves some credit for work in beginning development, manufacturing and distribution of the vaccine, citing former Health and Human Services Assistant Secretary Admiral Brett Giroir, who recently vented frustration about the Biden administration’s repeated claims that the Trump team left it empty-handed. But Psaki pushed back strongly.

“We are open-eyed about the challenge we continue to live under, and that's why he has been focused every single day and doing everything possible to get the pandemic under control. But there were shortages in all of those areas which were preventing us from moving forward on getting the pandemic under control,” Psaki said.

In the past, Biden himself has acknowledged the Trump administration's efforts, saying in January, "We want to give credit to everyone involved in this vaccine effort and the prior administration and the science community and the medical sphere…for getting the program off the ground."

-ABC News' Sarah Kolinovsky

Following her East Coast school swing, first lady Jill Biden will head to the West Coast on Tuesday and Wednesday to visit military bases in Washington state and California to connect with military families.

"These visits are part of the First Lady’s on-going efforts to listen and learn directly from military families about the unique challenges they are facing and the support they need, especially during the pandemic," the White House said in a statement about the trip.

-ABC News' Molly Nagle

ABC News Senior White House Correspondent Mary Bruce pressed White House press secretary Jen Psaki on Thursday about Biden's pandemic response, including his reaction to the governors of Texas and Mississippi eliminating mask mandates and allowing businesses to open at 100% capacity.

Bruce asked Psaki about the president saying those moves represented "neanderthal thinking" and asked whether that stance would help convince people to follow health measures.

Psaki said the president's comments were a "reflection of his frustration and exasperation" -- a year into the pandemic -- with decisions not consistent with science.

She also responded to a question about whether the White House would recommend people not travel to states like Texas and Mississippi as a result of those states' policies.

"We are going to continue to use every method of the bully pulpit at our disposal to convey directly to people living across the country, including in many of these states, that mask-wearing, social distancing getting access to the vaccine is the path to go back to normal," Psaki said.

Secretary of Veteran's Affairs Denis McDonough joined the White House press briefing on Thursday to discuss the effects of the COVID-19 pandemic on veterans and the ongoing efforts to get veterans vaccinated.

"Countless veterans have lost jobs, closed businesses, home-schooled their own children, and faced uncertain prospects while our nation grappled with the pandemic," McDonough said. "And like the rest of the country, many veterans were directly affected by the deadly virus, with more than 230,000 veterans in our care infected by it and, sadly, 10,605 dying from the disease."

McDonough says that even though the VA has infrastructure to get the vaccines out the greatest challenge is "supply."

"So the big challenge for us is supply. From what I hear from our [doctors] is, from the moment we get it, our allotments are in arms within two to three days," McDonough said.