There "will be no interruption" to UK vaccine supplies, Cabinet Office minister Michael Gove has said, after the EU urged AstraZeneca to supply it with doses from UK plants.
"It is the case that the supplies that have been planned, paid for and scheduled should continue," he added.
The EU and AstraZeneca are involved in a row over vaccine supply shortages.
Sir Jeremy Farrar, a scientific adviser to the UK government, said vaccine nationalism did not serve anyone.
The EU has demanded that UK-made jabs are diverted to mainland Europe to fulfil contractual obligations.
AstraZeneca has previously said it could deliver only a fraction of the doses between January and March that it had promised to the bloc, blaming production issues at EU plants for a reported 50 million-dose shortfall.