The chief of staff also told Hahn his job was in jeopardy if the emergency use authorization was not issued before Saturday, said a second administration official familiar with the conversation.
Hahn signaled that he would tell regulators to allow the vaccine to be issued on an emergency basis, the official said.
Friday's threat marked the latest attempt by the Trump administration to override government scientists working to combat the deadly pandemic. Even with an FDA decision expected within hours, President Donald Trump and his deputies proved unwilling to let regulators work through their careful review, which includes drafting safety warning labels and instructions for physicians.
“Get the dam vaccines out NOW, Dr. Hahn,” Trump tweeted Friday. “Stop playing games and start saving lives.”
“This is an untrue representation of the phone call with the Chief of Staff," Hahn said in a statement. "The FDA was encouraged to continue working expeditiously on Pfizer-BioNTech’s EUA request. FDA is committed to issuing this authorization quickly, as we noted in our statement this morning.”
The FDA said earlier Friday that it "will rapidly work” to grant emergency use of the vaccine.