The EU and the UK-based Covid vaccine maker AstraZeneca have vowed to work together to resolve a bitter row over supply shortages to the 27-member bloc.

This comes after crisis talks which both sides described as "constructive".

AstraZeneca earlier said it could deliver only a fraction of the doses it promised in January-March, blaming production issues at European plants.

But the EU said the firm must honour its commitments and deliver the jabs by diverting stock from the UK.

The contract between the EU and AstraZeneca contains a confidentiality clause - but the EU has asked the company to release the details nevertheless.

Reports said last week the EU would get 60% fewer vaccine doses - about 50 million jabs - than promised in the first quarter of the year.

The AstraZeneca vaccine, developed with Oxford University, has not yet been approved by the EU, although this is expected on Friday.

The EU - which has been criticised for the slow rollout of its inoculations - is also facing delays with supplies of the Pfizer-BioNTech vaccine. The bloc has a much bigger deal with the US-German vaccine-maker.

Meanwhile, UK Prime Minister Boris Johnson said: "I'm confident of our supplies and we'll keep rolling out vaccines as fast we possibly can. I am very pleased at the moment that we have the fastest rollout of vaccines in Europe by some way."

What did the EU and AstraZeneca say?

After Wednesday's crisis talks, EU Health Commissioner Stella Kyriakides expressed regret over the "continued lack of clarity on the delivery schedule".

"We will work with the company to find solutions and deliver vaccines rapidly for EU citizens," she tweeted.

An AstraZeneca spokesman said the company had "committed to even closer co-ordination to jointly chart a path for the delivery of our vaccine over the coming months".

Kyriakides stressed before the talks that UK factories, which have not experienced production problems, were part of its deal with the company and had to deliver.

"The 27 European Union member states are united that AstraZeneca needs to deliver on its commitments in our agreements," she said.