Italy has blocked the export to Australia of 250,000 AstraZeneca coronavirus vaccine doses, amid a dispute with the drug manufacturer over delivery shortfalls inside the European Union, the Italian foreign ministry said Thursday.

The move was the first time an E.U. country used new powers introduced in January, after AstraZeneca announced it would deliver sharply fewer doses to the E.U. than promised for the first months of the year.

Italian leaders proposed the block on the Australian shipment, and E.U. policymakers in Brussels signed off on it, the Italian foreign ministry said in a statement.

The decision to block the doses was because of “the lingering shortage of vaccines in the E.U. and in Italy, and the delays in the supply of AstraZeneca vaccines to the E.U. and Italy,” among other reasons, the statement said.

The blocked doses were being injected into vials in Anagni, a town outside Rome, at a plant owned by Catalent, a New Jersey-based drug company.

A spokesman for AstraZeneca declined a request for comment. Australian officials did not respond.

The move could further concerns about vaccine nationalism and inflame international tensions about access to vaccines.

“Blocking exports to meet domestic vaccination targets is a very dangerous card for policymakers to play,” said John Denton, the secretary general of the Paris-based International Chamber of Commerce, in a statement. He warned that global supply chains could quickly be disrupted as other countries retaliate.

AstraZeneca has said it can deliver 40 million doses to the E.U. by the end of March. That’s half of what the company had originally pledged, and an equivalent shortfall is expected for the second quarter of the year. Company executives have blamed manufacturing problems.

But many E.U. countries say AstraZeneca is not being fully transparent — and they suspect the company is shortchanging the E.U. in the interest of fulfilling contracts with other countries.

The European Commission announced in January that it would require vaccine manufacturers to ask permission of national governments before they could export doses outside of the bloc.

Italian Prime Minister Mario Draghi, who took office last month, has been among the most aggressive E.U. leaders saying that doses made in the bloc should stay in the bloc. He pushed for more controls at his first E.U. summit last week, diplomats said. And in a conversation with European Commission President Ursula von der Leyen on Wednesday, he declared that he wanted to “suffocate” the drug companies to make sure they met their E.U. contracts, Italy’s La Repubblica newspaper reported.

When the E.U. export controls were announced, European leaders said they would not apply to the neediest countries. But that list did not include Australia. A previous shipment of 142,000 E.U.-made doses of the Pfizer vaccine made it to Australia last month, as did 300,000 AstraZeneca doses over the weekend.

Australia began its vaccination campaign Feb. 22 — nearly two months after the E.U. As a result, it is further behind. It has administered 47,759 doses, or 0.19 per 100 people. Italy has about 2½ times the people, but has administered about 100 times the doses.

Yet Italy and the broader E.U. are concerned about the pace of their vaccination campaigns as the virus continues to spread. They are far behind the United States, Britain and Israel in getting their citizens vaccinated, the result of a slow rollout, delivery delays and mixed messaging from leaders.

French President Emmanuel Macron was among those who initially questioned the AstraZeneca vaccine’s efficacy in older people, noting there was limited clinical data on that population. About half of E.U. countries initially banned the vaccine for people over 65, though real-world data from Britain prompted reversals in France, Germany and elsewhere this week.

Still, some Europeans have been reluctant to get a vaccine that in clinical trials was somewhat less effective than competing vaccines in preventing symptomatic disease.

Italy has received 1.5 million doses of the AstraZeneca vaccine but has administered only 323,000 of them, according to official data.

Birnbaum reported from Riga, Latvia, Ariès reported from Paris and Pitrelli reported from Rome. Chico Harlan in Rome contributed to this report.