WASHINGTON (AP) — The head of the agency responsible for authorizing COVID-19 vaccines said Tuesday that it would take the time needed to “get this right,” despite increasing pressure from President Donald Trump to speed up the process.

“No one at FDA is sitting on his or her hands. Everyone is working really hard to look at these applications and get this done,” Stephen Hahn, the head of the Food and Drug Administration, told ABC in an interview on Instagram Live. “But we absolutely have to do this the right way.”

Hahn’s comments came not long after he was summoned to the White House by Trump’s chief of staff Mark Meadows as the agency weighs whether to allow emergency use of the first vaccines that could begin the long road to defeating the coronavirus in the U.S.

Trump has been livid with the FDA for not moving faster to approve the shots, blaming the fact that a vaccine was not available ahead of the Nov. 3 election in part for his loss. He also has leveled unfounded claims that drug companies deliberately delayed vaccine development to hinder his reelection chances, though there is no evidence to suggest that took place.

As he has refused to accept his loss, Trump also has told close confidants that he believes the vaccine is still being slow-walked in a bid to undermine his efforts to challenge the results. If the vaccine were shipped out sooner, he has argued, it would rally public opinion to his side.

Hahn emerged from the White House meeting with his job intact, but it was a sign of the pressure he is under that the FDA offered guidance that “Dr. Hahn remains FDA Commissioner.”

Hahn said the FDA will thoroughly review each vaccine before making it available to the public.

“We will make sure that our scientists take the time they need to make an appropriate decision,” Hahn said in a statement provided by the FDA. “It is our job to get this right and make the correct decision regarding vaccine safety and efficacy.”

An FDA spokesman said the agency must review thousands of pages of technical information provided by vaccine developers to ensure the shots were studied and manufactured properly.

As for the meeting, Hahn told ABC that it was held “to provide a briefing around the issues we’re discussing here and that’s what occurred.”

The FDA has been weighing whether to authorize two experimental vaccines that have been raced through development. Pfizer and Moderna are seeking “emergency use” that would allow people in high-risk groups to get vaccinated while final-stage testing continues.

But the meeting risked exacerbating concerns that many Americans already harbor about the potential impact of political pressure on vaccine development. Public health officials, including Hahn, have been trying to provide reassurance for months that the approval process has been free from influence.

Meanwhile, a separate scientific panel was tackling the pressing question of who should first receive vaccinations when they become available in limited supply.

The White House did not respond to requests for comment about the meeting with Hahn and his future at the agency. But many aides to the president recognize that it would look especially bad for Trump to lose Hahn on the cusp of vaccine authorization.

The president has been fuming about the pace of the vaccine approval process since he lost his reelection bid and believes that, had Pfizer and Moderna released data showing their vaccines were effective before Election Day, he would have have won the race. He has also complained repeatedly about not getting the credit he believes he deserves for the vaccines’ development and has urged reporters not to give President-elect Joe Biden credit for what has happened on Trump’s watch.

In the first months of his tenure, former FDA staffers and outside experts criticized Hahn, a scientific researcher and former hospital executive, for decisions that many viewed as bowing to the White House and failing to protect the agency’s science-based decision-making process.