Clinical trials for AstraZeneca’s coronavirus vaccine candidate have been halted in India, says Serum Institute of India.

Serum Institute of India is the world’s largest manufacturer of vaccines by volume and has said it will mass-produce the vaccine candidate developed by the University of Oxford.

On Tuesday, AstraZeneca had said in a statement that a potentially unexplained illness in a recipient had triggered a “standard review process” and that late-stage studies were put temporarily on hold. Serum Institute of India, though, had said that trials in India were continuing.

But after official communication from Indian regulators, the company paused their trials today.