By Andreas Stein

Chernobyl, Ukraine - After reports of blue dogs running around the exclusion zone near Chernobyl went viral, experts have seemingly set the record straight.

Serhij Kirjejew, who is the general director of the state-owned company Ecocentre that monitors the zone, shut down the speculation when speaking with reporters.

"That's nonsense," Kirjejew said.

"The dogs have been sterilized, and they are marked in blue that they have been sterilized."

The sterilization is done to "contain" the dog population, and the blue hue is "harmless" to them.

News of the blue dogs near the site of the infamous disaster had made international headlines, and images shared by Dogs of Chernobyl – which looks after the canines – went viral online.

"We are not sure exactly what is going," the animal rights activists had said. "The town people were asking us why the dogs were blue? We do not know the reason and we are attempting to catch them so we can find out what is happening."

The explosion at Chernobyl in April 1986 remains the worst nuclear disaster in history. Dozens were killed in the explosion, and villages near the then-Soviet nuclear power plant had to be evacuated.

Tens of thousands of people were relocated, and thousands suffered radiation damage.

Dogs left behind multiplied, and there is still a population of street dogs today.