The EU executive is suing British-Swedish pharmaceutical group AstraZeneca to force it to deliver 90 million more doses of its Covid-19 vaccine before July, a spokesman said on Tuesday.
"We want the court to order the company to deliver 90 million additional doses, in addition to the 30 million already delivered in the first quarter," European Commission spokesman Stefan De Keersmaecker told a media conference.
The demand stems from a row between Brussels and AstraZeneca over a shortfall of tens of millions of vaccine doses the company was meant to have delivered to the EU since the beginning of the year.
The commission has launched two emergency legal actions against the company in a Belgian court, first to have the urgency of the issue recognised, and then to have a judge rule on whether the EU's case is well-founded.
The European Commission, backed by the 27 EU member states, argues that AstraZeneca has breached a contract stipulating it would deliver 300 million vaccine doses to the EU in the first half of this year.
AstraZeneca has responded that it is bound only by a "best reasonable efforts" to meet that target.
After citing production problems in its EU manufacture, and refusing to divert doses from British factories listed as suppliers in the EU contract, the company offered revised deliveries.
Instead of 120 million doses originally promised for the first three months of this year, it delivered 30 million. For the second quarter, when it was to have supplied 180 million doses, it vowed it would instead deliver 70 million.
An EU official with knowledge of vaccine deliveries told AFP that AstraZeneca's current rhythm of 10 million doses delivered per month fell even short of that diminished schedule.
De Keersmaecker said the aim of the lawsuits was not to punish AstraZeneca with a fine or seek compensation but "to make sure that the doses are delivered". If a fine would spur the company to meet its obligations "we could ask them to pay a fine".
He said the Commission would only lay its arguments out in the court room, not in a media conference, but added: "We are convinced that we have a very sound argument in demanding what we're demanding before the courts."
The legal action piles further pressure on AstraZeneca after a link was made between its vaccine and very rare but often fatal blood clots coupled with low platelet levels.
After the European Medicines Agency said that the benefits of the AstraZeneca vaccine outweighed the risk for all adults, the European Commission maintained AstraZeneca as one of the four vaccines it offers to member states.
But many EU countries have restricted AstraZeneca jabs to older people only, typically over 55 or 60. One, Denmark, has abandoned the vaccine entirely.
Non-EU member Norway has also received a recommendation from experts to drop AstraZeneca, while experts in Britain, a former EU member, recommended people under 40 be given an alternative vaccine.