"The company has not been in the position to come up with a reliable strategy to ensure the timely delivery of doses," said a European Commission spokesperson.
The European Union says it has launched legal action against AstraZeneca over alleged breach of contract concerning delivery of its coronavirus vaccine.
"The European Commission has started last Friday legal action against the company AstraZeneca on the basis of breach of the advanced purchase agreement," said a spokesperson from the European Commission.
AstraZeneca had committed to supplying 180 million doses to the EU in the second quarter of this year but has faced multiple delays to shipments.
The vaccine was a key part of the bloc's vaccination plan. It is cheaper and easier to use than rival shots from Pfizer and Moderna and has been endorsed for use in over 50 countries.
EU officials have accused the company of failing to deliver on its commitment.
"The company has not been in the position to come up with a reliable strategy to ensure the timely delivery of doses. What matters to us, in this case, is that we want to make sure that there's a speedy delivery of a sufficient number of doses that European citizens are entitled to and which have been promised on the basis of the contract," European Commission spokesman Stefan De Keersmaecker continued.
"So the Commission has indeed started legal action on its own behalf and on behalf of the 27 member states that are fully aligned in their support for this procedure."
Last month, European Commission President Ursula von der Leyen accused AstraZeneca of having "unfortunately under-produced and under-delivered".
At the time, she said the EU was expecting to receive 70 million vaccine doses from the drugmaker, far less than had been expected.
As a result, she said: "This painfully, of course, reduced the speed of the vaccination campaign.”
The EU has been highly critical of the company since it emerged it would miss its targets for delivering doses to the EU - but remained on course with its deliveries to the UK.
The situation led to the EU threatening to block vaccine exports from the bloc to certain countries, as its vaccination programme fell behind other countries such as the UK and US.
The Anglo-Swedish pharmaceutical only delivered about half of the doses it was contracted to in the first three months of the year.
It has also already announced that it would miss its delivery target to the bloc in the second quarter as well.
AstraZeneca said in a statement it “regrets” the EU’s decision.
“Following an unprecedented year of scientific discovery, very complex negotiations, and manufacturing challenges, our company is about to deliver almost 50m doses to European countries by the end of April, in line with our forecast,” the company said.
“AstraZeneca has fully complied with the Advance Purchase Agreement with the European Commission and will strongly defend itself in court. We believe any litigation is without merit and we welcome this opportunity to resolve this dispute as soon as possible.”
The latest move from the EU comes amid concerns that rare blood clot cases could be linked to the vaccine, with a number of countries pausing the rollout of the jab.
Others have changed the guidance on which age groups should be given the vaccine.
The European Medicines Agency confirmed a "possible link" between the jab and the blood clots in early April.