Germany, France, Spain, Italy, Ireland and the Netherlands have joined the growing list of countries that have suspended the use of the coronavirus vaccine developed by AstraZeneca and the University of Oxford over blood clot concerns.

The Dutch government said Sunday that the Oxford-AstraZeneca vaccine would not be used until at least March 29, while Ireland said earlier in the day that it had temporarily suspended the shot as a precautionary step.

On Monday, the German government also said it was suspending its use, with the vaccine regulator, the Paul Ehrlich Institute, calling for further investigations. The Italian medicines authority made a similar announcement on Monday afternoon and French President Emmanuel Macron also said the vaccine’s use would be paused pending a verdict from the EU’s regulator. Spain Health Minister Carolina Darias said Monday that the country will halt use of the shot for at least two weeks, Reuters reported, and Portugal and Slovenia also suspended the vaccine.

The World Health Organization has sought to downplay ongoing safety concerns, saying last week that there is no link between the shot and an increased risk of developing blood clots. The United Nations health agency has urged nations to continue using the Oxford-AstraZeneca vaccine.

Despite this, a number of European countries have already paused the use of the Oxford-AstraZeneca vaccine. It has added to the woes of the region’s ailing vaccination campaign at a time when Germany’s public health agency has warned that a third wave of coronavirus infections has already begun.

Thailand has also halted its planned deployment of the vaccine.

The move to pause its use by Dutch and Irish officials came shortly after Norway’s medicines agency said it had been notified of three health workers being treated in hospital for bleeding, blood clots and a low count of blood platelets after receiving the Oxford-AstraZeneca vaccine. Norway has put its Oxford-AstraZeneca vaccine program on hold.

Geir Bukholm, director of the division of infection control and environmental health at the Norwegian Institute of Public Health, said Norway’s medicines agency would “follow up on these suspected side effects and take the necessary measures in this serious situation.”