Residents of Russia's Yaroslavl region got a scare when local TV and radio stations broadcast a radiation warning, but the Emergency Situations Ministry said the broadcast was a mistake.
The prerecorded warning, which aired at about 9 a.m., alerted residents to what it said were high levels of radiation in the atmosphere in the region 250 kilometers northeast of Moscow.
It advised people to protect themselves, tightly close their homes or offices and stay inside, and secure food and water from possible contamination by radiation.
In a statement, the regional branch of the Emergency Situations Ministry said that a technical glitch caused the "false" warning to be broadcast.
It urged residents to "remain calm" and said radiation levels were "within the norm."
In a short video statement, the senior regional emergency official, Yevgeny Shumilin, said the authorities were investigating what caused the message to be broadcast.