The pause is due to rare blood-clotting issues in adults who took it, pending further information about the vaccine.

No safety issues have been noticed in the trial, an Oxford spokesman said Tuesday, but broader concerns about clotting problems in adults triggered further regulatory reviews in the UK and Europe to probe into any potential link with the coronavirus vaccine.

Earlier, the European Medicines Agency (EMA) said it was investigating incidents with patients who received shots from one batch of AstraZeneca vaccines in several EU countries and who later had thromboembolic complications.

A number of European countries, including Austria, Estonia, Lithuania, Latvia, Luxembourg, Denmark, Bulgaria, Norway, Iceland, Slovenia, Cyprus, Italy, France, Germany and Spain, suspended the use of the AstraZeneca vaccine. The EMA later made a recommendation to continue using the medicine, after which a number of countries resumed vaccinations with it.