The European Union on Tuesday stepped up pressure on pharmaceutical companies it says have hobbled coronavirus vaccine rollouts, proposing tighter export controls and threatening potential legal action after two manufacturers announced sudden cuts to supply.

The bloc’s executive branch, the European Commission, said Tuesday that it was planning measures to have companies register their vaccine exports from the European Union. The proposal is aimed at increasing transparency, the commission said, but would effectively slow the flow of vaccine doses out of the 27-nation group.

The moves follow a dispute between the European Union and British-Swedish pharmaceutical firm AstraZeneca, which said last week that it would supply “considerably fewer” doses of its coronavirus vaccine to E.U. member states than originally planned. The company blamed reduced capacity at one of its European production sites.

“This new schedule is not acceptable to the European Union,” Health Commissioner Stella Kyriakides said Monday in a televised address. “The European Union wants to know exactly which doses have been produced by AstraZeneca and where exactly so far, and if or to whom they have been delivered.”

This month, U.S.-based pharmaceutical giant Pfizer, which also developed a vaccine, said it would curb its deliveries because of production delays at its Belgian plant. European leaders had hoped for a smooth vaccine rollout that would immunize the bloc’s 448 million residents.

E.U. states are considering ­suing AstraZeneca for breach of contract “if things do not improve,” Latvian Foreign Minister Edgars Rinkevics said. “We still hope that they will honor commitments, however all options are on the table.”

He said he was frustrated to watch vaccinations move more quickly in Britain and the United States, a situation E.U. policymakers have blamed on supply issues.

“That is why I get nasty on this,” Rinkevics said. “We will push the commission and others for coordinated and strong action. AstraZeneca got E.U. funding for vaccine development.”

Speaking during a European Parliament committee session, the executive director of the European Medicines Agency, Emer Cooke, said its ability to resolve production and supply problems is limited.

Responding to questions about the vaccine AstraZeneca developed with Oxford University, Cooke said the studies that have so far been submitted to the agency included only “a very small quantity of elderly populations” in their trials.

The agency is expected to announce a decision this week on whether to allow conditional use of the vaccine. Cooke did not indicate in which direction the agency is leaning.

“But it is possible to conclude an authorization that would focus on a particular age group, or it’s possible to conclude for a wider age group,” said Cooke, referencing concerns over the small number of elderly people included in past trials of the vaccine.

In an interview with France’s Le Figaro newspaper, the chief executive of French drugmaker Sanofi said Tuesday that it had struck an agreement with Pfizer and its German partner, BioNTech, to help distribute more than 100 million vaccine doses in Europe by the end of the year.

In Britain, more than 6.8 million people — more than 10 percent of the population — have received either the vaccine by Pfizer-BioNTech or the homegrown AstraZeneca-Oxford vaccine.

Britain’s vaccine minister, ­Nadhim Zahawi, said he was “confident” that the country would meet its target of vaccinating 15 million of its most vulnerable people by mid-February.

Britain was the first country to approve the Pfizer-BioNTech vaccine and the AstraZeneca-Oxford vaccine for widespread use outside clinical trials. It began its vaccination rollout Dec. 8.

On Monday, Germany’s health minister said he supported restricting vaccine exports to ensure doses reserved for E.U. member states remain in the bloc. Last year, Germany provided $455 million in federal funding to Pfizer and BioNTech for Stage 3 clinical trials and to boost production capacity.

For Europe, the lack of supply is particularly galling: Doses for countries outside the European Union are often produced in the bloc, which has spent $3.3 billion on funding the development and production of vaccines.

“Europe invested billions to help develop the world’s first covid-19 vaccines, to create a truly global common good,” the commission’s president, Ursula von der Leyen, said at a virtual meeting of the World Economic Forum on Tuesday. “And now, the companies must deliver. They must honor their obligations.”

Michael Birnbaum in Riga, Latvia, and Karla Adam in London contributed to this report.