BRUSSELS — The European Union is moving toward stricter export controls to ensure there are more COVID-19 vaccine supplies for the bloc.

European Commission President Ursula von der Leyen said on the eve of a summit of the 27 leaders that it has a plan ready to guarantee more vaccines produced in the bloc are available for its own citizens before they can be shipped for exports.

EU nations have been specifically stung by the United Kingdom, which has received some 10 million doses from EU plants while they say nothing came back from Britain. Prime Minister Boris Johnson has spoken in the past few days to European leaders, including von der Leyen and French President Emmanuel Macron.

“Vaccines are an international operation,” Johnson says, adding that the U.K. would “continue to work with European partners to deliver the vaccine rollout.”

The EU has been insisting that two AstraZeneca plants in Britain should also be part of the EU deliveries.