BERLIN (AFP, REUTERS) - AstraZeneca will deliver 30 per cent more coronavirus vaccine doses to the European Union than it pledged last week, European Commission chief Ursula von der Leyen said on Sunday (Jan 31).

The company will send 9 million additional doses and "will start deliveries one week earlier than scheduled", Von der Leyen said in a tweet after days of tensions over production delays.

An EU source said that the first deliveries would start in the second week of February.

AstraZeneca would also extend its production capacity in Europe, Von der Leyen added.

The EU leader sent the tweet after talks on Sunday with the leaders of the drugs companies that have signed vaccine contracts the EU.

She told Germany's ZDF broadcaster the new doses represented an increase of 30 per cent on the previous order.

The aim was still to vaccinate 70 per cent of adults in the EU by the end of summer, she added.

The EU has come under increasing pressure in recent days as it was forced to revise its original vaccination targets in the face of supply problems.

On Jan 19, it said it aimed to vaccinate 80 per cent of health professionals and people aged over 80 by March.

But AstraZeneca, whose vaccine was authorised for use in the EU on Friday, announced a three-quarters cut in the deliveries it had promised to the EU in the first quarter. It blamed production problems at one of its European sites.

Brussels refused to accept that explanation, demanding an inspection of the Belgian industrial site concerned, which is managed by a sub-contractor.

Germany's government on Sunday threatened any laboratory that failed to respect their obligations with legal action.

Von der Leyen also rejected suggestions that Europe was in a race to vaccinate its population against the coronavirus faster than other countries, saying that it was important to cooperate at this stage of the pandemic.

The European Union's civil service is under fire over the slow pace of vaccination in the bloc, with critics pointing to faster progress being made in Britain, Israel and the United States as evidence of a planning failure in Brussels.

"I think the only race we are in is with the virus and against time," Von der Leyen told German television on Sunday evening, adding that she had agreed with British Prime Minister Boris Johnson that factories in both regions would deliver doses to each region