Updated

A spokesman for Russian President Vladimir Putin says hundreds of bomb threats made by anonymous telephone callers against major public buildings in Russia this week amount to "telephone terrorism."

Dmitry Peskov said Thursday that "all necessary measures are being taken" to find the perpetrators, but refused to comment on who was behind the calls.

Tens of thousands of people have been evacuated in cities across Russia from schools, hospitals, hotels, shopping centers, airports, railways stations and universities targeted by the bomb threats since the weekend.

Dozens of buildings in Moscow and St. Petersburg were evacuated Thursday.

State-owned television channels — how most Russians get their news — have aired little coverage about the threats and there have been no official statements from security service officials investigating the hoax calls.