The European Union has told AstraZeneca to "catch up" with deliveries of its Covid-19 vaccine and says it should "honour the contract it has with member states".
The EU is struggling with the slow pace of its vaccine rollout and is unhappy with pharmaceutical companies - primarily AstraZeneca.
Some in the EU have claimed that AstraZeneca has shown preferential treatment to the UK - but the company denies this.
Where does the UK get its Oxford-AstraZeneca vaccine from?
The Oxford-AstraZeneca vaccine is made in the UK at two sites - in Oxford and Keele. A third plant in Wrexham puts the vaccine into vials and packages them up for distribution.
The UK has ordered 100 million doses. Almost all will come from within the UK, but 10 million doses are being made by the Serum Institute in India.
Half the consignment from India has been received, the other half has been delayed
Why is the EU unhappy with this arrangement?
The EU says the UK is receiving preferential treatment from AstraZeneca.
In January, AstraZeneca said it would have to cut the number of doses it could deliver to the EU. It blamed production delays.
The company said its agreement with the EU allowed the option of supplying Europe from UK sites, but only once the UK had sufficient supplies.
The full details of the company's deals with the UK and the EU have not been made public. But analysis by the Politico website points to a clause in the UK's contract which says the government "may terminate the deal and invoke what appear to be punishment clauses" if there is a delay in supply.
According to Politico, the EU waived its right to sue the company in the event of delivery delays. The European Commission says it is now involved in a "dispute mechanism" with AstraZeneca.
Where is the EU's AstraZeneca vaccine manufactured?
The EU has ordered 400 million doses of the Oxford-AstraZeneca vaccine.
The company says supplies are coming mainly from the US and Seneffe in Belgium.
A site in Leiden in the Netherlands is also expected to produce vaccines for the EU.
In total, AstraZeneca say it's working with suppliers in 15 countries.
AstraZeneca confirmed the UK had not received any vaccines or components from the EU - apart from one "tiny" batch from the Leiden plant.
Is the EU running out of AstraZeneca doses?
No - in fact, EU countries have been reporting hundreds of thousands of unused doses because of a drop in public confidence in the jab.
France has used53% and Germany 68% of the AstraZeneca jabs they have received, according to the latest figures European Centre for Disease Prevention and Control (ECDC).
The Netherlands has used only 44% of its supply.
Italy, Spain, Austria, Greece and Sweden are among other EU countries where the proportion of unused AstraZeneca vaccine is much higher than the proportion of unused Pfizer jabs.
What about other vaccines?
The Pfizer jab is mostly made in Puurs in Belgium, and a manufacturing site has also been set up in the German town of Marburg.
The UK has ordered 40 million Pfizer doses.
The European Commission says about 11 million doses have been exported to the UK from the EU since early February.
It says no vaccines have come the other way. The UK government has not confirmed whether there have been any doses exported to the EU.
Vaccines may be produced in one place but "filled and finished" - put into vials and prepared for export - in another.
And some components used in the process may be made at yet another location.
For example, the UK company Croda is supplying a component to Pfizer to make its vaccine.