ISTANBUL — Turkey has suspended flights to Iran and Afghanistan as part of measures against the coronavirus outbreak, the Transport Ministry said on Sunday.

Turkish Airlines had gradually restarted international flights as of June 11.

A spokesman for Iran’s Civil Aviation Organization, Reza Jafarzadeh, confirmed the flight suspension, according to the official IRNA news agency.

Iranian President Hassan Rohani said on Saturday that 25 million people may have been infected with the coronavirus in Iran, although health officials later sought to play down the estimate.

The 25 million figure put forward by Rohani 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 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.

"It is not possible to rely on serological tests to diagnose the current state of the disease," the statement said.

Serological tests determine if a person has been exposed to a disease by showing their antibody response. In the coronavirus pandemic, they have been used by countries to survey samples of the population and estimate overall infection rates — whether or not people have had severe, mild or no symptoms of COVID-19. — Agencies