Iranian health officials sought on Sunday to play down the president’s estimate that some 25 million people have been infected with the coronavirus, saying it was based on serological blood tests that measure exposure to the illness and that cannot be relied on to show the current state of disease.

The 25 million figure put forward by President Hassan Rouhani on Saturday is nearly a third of the population and massively higher than the official number of COVID-19 cases. Official case numbers rose to 273,788 on Sunday, with 14,188 deaths, Health Ministry spokeswoman Sima Sadat Lari said.

A Health Ministry statement carried by Iranian news media said the figure given by the president was based on numbers produced by a deputy in the ministry.