"This is not within the competence of the EMA so I can only speak from a personal perspective, where I really believe we need to ensure access, availability and access throughout the world, not just in the countries that have the means to pay for them," EMA Executive Director Emer Cooke said in an interview.
Spain introduced the restriction on Wednesday after the European Medicines Agency reported a link between the shots and a rare form of brain blood clots affecting roughly one in every 100,000 people under 60 vaccinated.
As of Thursday night, only around 45% of people had confirmed their vaccine appointments for Friday, he added.
Four serious cases of rare blood clots with low platelets, one of which was fatal, have been reported after inoculation with J&J's vaccine from its Janssen unit, the European Medicines Agency said, adding five cases of capillary leak syndrome linked to AstraZeneca's vaccine were reported.
His comments came as the European Medicines Agency and Britain's medical regulator acknowledged a possible link between the AstraZeneca vaccine to very rare cases of unusual blood clots with low blood platelets, with most cases reported in women under 60 years of age within two weeks of vaccination.
Conservative leader Kurz is under fire from opposition parties because his government did not buy as many coronavirus vaccines as it could have under the European Union's collective purchasing scheme.
"There must be no geopolitical blinkers regarding vaccines," Kurz said in a statement issued by his office, adding that Austria is in talks with Russia and Moscow has offered to sell it a million doses as of April. "The only thing that must count is whether the vaccine is effective and safe."
It said it would investigate reports of clots in the cerebral veins (sinus vein thrombosis, or CSVT) occurring together with lowered platelets soon after vaccination. But the agency said use of the vaccine should continue and one official said Britain's rollout would likely not stop even if a link was proved.