Tsarevo mayor Marin Kirov said he will order checks on livestock farmers who keep guard dogs. He made the announcement after he and a colleague freed a dog from rising flood water near the concrete plant in the town.

It happened at about midnight, when the rain was heaviest. The dog was stuck by the water and could not get out on its own. It is not known who owns it or in what conditions it was left there.

There was no prior alert and no organised rescue. Kirov spotted the dog by chance as the two men were passing. They stopped and freed it.

A woman was the first to write about it on Facebook, where she praised the mayor. She said the dog would have drowned because of its owner's irresponsibility. She also said real leaders do not stay in their offices when there is danger, that humanity and morals are proved by deeds, and that in Tsarevo every life matters.

Kirov replied under her post. "First, I was not alone, I was with a colleague with a big heart," he wrote. The colleague's name has not been given.

The mayor said the dog was in real trouble and was lucky they stopped, because he had only seen it out of the corner of his eye. He added that people like the author of the post and her family make him think about animals too.

"We will order checks and issue instructions to all livestock farmers along the Chernaya river to start taking care of the dogs they use as guards," Kirov said. Dogs guard farms and other sites in the area.

Guard dogs depend entirely on their owners. If they are tied up or shut in a dangerous spot, they cannot save themselves in a flood. The checks are meant to find out whether any rules were broken and what steps are needed to stop this happening again.