The Trump administration attempted to persuade a German firm developing a possible vaccine for coronavirus to move its research work to the United States, German officials said, raising fears in Berlin that President Trump was trying to assure that any inoculation would be available first, and perhaps exclusively, in the United States.

The offer arose from a March 2 meeting at the White House that included the chief executive of the German firm CureVac, Daniel Menichella. President Trump briefly attended the meeting and Vice President Mike Pence, who heads the White House coronavirus task force, was also there.

âoeWe are very confident that we will be able to develop a potent vaccine candidate within a few months,â Mr. Menichella said in a statement on the day of the meeting.

But four days ago, CureVac announced that Mr. Menichella, an American, was leaving the biotechnology company, which he had headed for two years.