The chief executive of pharmaceutical company AstraZeneca has vowed to resist pressure from the European Union to divert doses of COVID-19 vaccine intended for the United Kingdom, following problems with supplies to the 27-member bloc, saying the UK gets priority as it signed its contract first.

There were even reports that the company had pulled out of a planned meeting over the issue, although this was later denied.

Vaccines made by both Pfizer/BioNTech and Oxford University/AstraZeneca have been approved and are being used in the UK, whereas so far the EU has only approved and used the Pfizer jab, with the AstraZeneca one expected to be given the green light later this week.

However, the company has already indicated that its first quarter supply to the EU is likely to be around 60 percent less than was expected, because of production problems.

"The EU and others helped with money to build research capacities and production facilities," the president of the European Commission, Ursula von der Leyen, said in a speech on Tuesday. "Europe invested billions to help develop the world's first COVID-19 vaccines to create a truly global common good. And now, the companies must deliver. They must honor their obligations."

Italy's government, which has just seen Prime Minister Giuseppe Conte step down, partly because of divisions caused by handling of the pandemic, wants to take both Pfizer and AstraZeneca to court over supply problems.

"We are starting legal action to get the doses, not financial compensation," Foreign Minister Luigi di Maio said at the weekend.

But Pascal Soriot, head of AstraZeneca, told Italian newspaper La Repubblica "the UK agreement was reached in June, three months before the European one.

"As you could imagine, the UK government said the supply coming out of the UK supply chain would go for the UK first. Basically, that's how it is," adding that it was even possible that up to 30 million people could be vaccinated by March. Such a prospect would be hugely welcome news in a country that on Tuesday passed the 100,000 death mark, a figure that has risen sharply from 50,000 in early November. By contrast, so far the EU has managed to vaccinate just 2 percent of people.

The Daily Telegraph reports that Italy, Germany, France and the Netherlands had all reached preliminary supply deals with AstraZeneca in June, but the European Commission insisted on one bloc-wide deal, which was not agreed for another two months.

When asked if the EU had left it too late, Soriot replied: "I will not pass judgment on this. But I can only tell you the facts … the UK contract was signed three months before the European vaccine deal. So with the UK we have had an extra three months to fix all the glitches we experienced. As for Europe, we are three months behind in fixing those glitches."