The remark was made hours after the two companies said their experimental vaccine was more than 90% effective, in what could be a major victory in the fight against the coronavirus pandemic.

The European Commission, which is negotiating with vaccine makers on behalf of EU states, had said in September it had concluded exploratory talks with U.S. pharmaceutical giant Pfizer and its German partner BioNTech over the supply of 200 million doses of their potential COVID-19 shot, with an option to buy another 100 million.

However, a deal has not been announced yet.

"EU Commission to sign contract with them soon for up to 300 million doses," von der Leyen wrote on Twitter.

Minutes earlier, a prominent centre right lawmaker in the EU Parliament had said a deal was imminent.

"According to my information, the respective contract is about to be signed," Peter Liese said.

The EU has already signed supply deals with AstraZeneca, Sanofi and Johnson & Johnson for their potential COVID-19 shots.

The United States, Japan and Britain have announced supply deals with Pfizer/BioNTech.

Data on the Pfizer/BioNTech vaccine have been assessed since early October by the EU drug regulator, the European Medicines Agency (EMA), under an extraordinary rolling review meant to speed up the possible approval of the shot.

The EMA said in an email to Reuters on Monday it had not received the latest results from large-scale trials, but it had evaluated non-clinical data.

It added that it was currently assessing a second batch of data on the quality of the vaccine, including those related to its ingredients and the way it is produced.

(Reporting by Francesco Guarascio @fraguarascio; Editing by Mark Potter and Ed Osmond)

By Francesco Guarascio