Russia is facing a “serious situation” as the coronavirus spreads, Moscow’s mayor told President Vladimir Putin on Tuesday as the official number of infections neared 500.

Russia has reported a total of 495 coronavirus infections so far, a number that observers have questioned due to the relatively low number of tests the country has carried out. Putin previously dismissed concerns over the coronavirus, saying the situation is “under control” in Russia and that the number of infections was “contained.”

“The momentum is high and a serious situation is unfolding,” Mayor Sergei Sobyanin, who heads Russia’s official coronavirus response body, told Putin.

“The real number of those who are sick is significantly higher” than official numbers indicate, Sobyanin said.

“The fact is that testing volume is very low, and no one on earth knows the real picture,” he said. He pointed to the fact that many Russians who returned from abroad have simply self-isolated at home and haven’t been tested for the virus.

Sobyanin said the coronavirus response team has prepared instructions for Russia’s regions that include the number of hospital beds and ventilators each region needs.

“All regions, without exception — regardless of whether they have coronavirus patients or no patients — everyone needs to prepare,” he said.

Sobyanin also stressed that Russia should introduce a nationwide home-confinement order for people over 65 years old to prevent the virus from spreading to them. Moscow has ordered all over-65s to stay home starting Thursday.

“Otherwise, the [health care] system simply will not cope,” he said.