The pharmaceutical giant told the European Commission on Friday there would be delivery delays in the first quarter of this year - a week after Pfizer made a similar announcement.

Ministers in Britain, where AstraZeneca's vaccine was principally developed, said they opposed protectionism "in all its forms".

The EU Steering Board - made up of health officials from the Commission and member states - held a virtual meeting with AstraZeneca on Monday afternoon to discuss the issue but "the answers of the company have not been satisfactory so far," Health Commissioner Stella Kyriakides said in a statement.

A second meeting was held on Monday evening.

"The European Union will take any action required to protect its citizens," Kyriakides said in the statement.

She said the company's announcement that it intends to supply "considerable fewer doses" than agreed "is not acceptable", stressing that the bloc had "pre-financed the development of the vaccine and the production and wants to see the return."

"We want clarity on transactions and full transparency concerning the export of vaccines from the EU.

"In the future, all companies producing vaccines against COVID-19 in the EU will have to provide early notification whenever they want to export vaccines to third countries," she added. Humanitarian deliveries would not be affected.

Matt Hancock, the UK Health Secretary, said he was "confident" that the supply of Pfizer and AstraZeneca vaccines in his country would not be disrupted.