The European Union is poised to tighten rules on the export of COVID-19 vaccines, risking a major escalation in the global battle to secure access to the life-saving shots.

With EU governments under fire over the shortfall in deliveries from drugmakers including AstraZeneca Plc, the EU’s executive arm will on Friday require companies seeking to ship the inoculations outside the bloc to obtain prior authorization.

European Council President Charles Michel has also raised the prospect of effectively seizing control of vaccine production if those measures fail to get the program back on track, a European official said.