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.”

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.”