European Union leaders have stopped short of banning vaccine exports after a protracted row with the Anglo-Swedish manufacturer AstraZeneca.
At a summit on Thursday they gave backing in principle for toughening export controls.
But a post-summit statement emphasised the importance of global supply chains needed to produce vaccinations.
Elements of the AstraZeneca vaccination are manufactured in a number of EU states.
European Commission President Ursula von der Leyen said AstraZeneca must "catch up" on deliveries to the EU before exporting doses elsewhere.
French President Emmanuel Macron told reporters this marked "the end of naivety" from the EU.
Vaccine rollouts in EU states have started sluggishly, and the bloc has blamed pharmaceutical companies - primarily AstraZeneca - for not delivering promised doses. AstraZeneca has denied that it is failing to honour its contract.
"I think it is clear that first of all the company has to catch up," Mrs von der Leyen told a news conference after the virtual leaders' summit.
"[It] has to honour the contract it has with European member states before it can engage again in exporting vaccines," she said. "We want to explain to our European citizens that they [can] get their fair share."
The EU was accused, primarily by the UK and the World Health Organization (WHO), of so-called vaccine nationalism after it introduced export controls on jabs produced within the bloc.
In response, UK Prime Minister Boris Johnson warned that "blockades" were not "sensible".
He said a ban would imperil the UK's vaccination drive, which has so far been more successful than EU member states' vaccine programmes.
Mr Johnson also warned that a ban that extended beyond AstraZeneca's disputed supply could also block jabs produced for BioNTech/Pfizer in Belgium.
But Mrs von der Leyen hit back on Thursday, arguing the EU was the "region that exports most vaccines worldwide".
"We invite others to match our openness," she said. The EU chief earlier tweeted that the EU had exported some 77 million doses to 33 countries since December,
Her comments came a day after the EU issued a joint statement with the UK in which both sides pledged to work together after weeks of tensions over the Oxford-AstraZeneca jab.
Meanwhile, French President Emmanuel Macron backed the EU's export controls.
"I support the fact that we must block all exports for as long as some drug companies don't respect their commitments with Europeans," he said.
Earlier, he expressed frustration at the slow pace of much of Europe's vaccine rollout. "We didn't shoot for the stars," he told the Greek television channel ERT before the summit. "We were wrong to lack ambition."
German Chancellor Angela Merkel also said the EU "not only supplies itself, but also exports to the world - in contrast to the US and Great Britain".
Dutch Prime Minister Mark Rutte said while his fellow leaders had found the Commission's tougher export measures "acceptable", he hoped they would never be used - a message echoed by his Belgian counterpart, Alexander De Croo.
Both those two countries are home to factories involved in the production of the AstraZeneca shot, which it's suggested may soon be sending increased supplies to European nations - a move that may assuage some EU anger, BBC Brussels correspondent Nick Beake reports.
Mr Rutte said an agreement with the UK over AstraZeneca components produced in the Netherlands could be announced this weekend.