MOSCOW (AP) — Russian health officials say that at least 30 people in a Siberian city have died of alcohol poisoning after drinking a bath lotion.

Tatiana Lebedeva of the local health department said Monday that 30 people had died of methanol poisoning after consuming the bath lotion containing alcohol in Irkutsk, Russia's sixth-largest city with a population of 1.1 million. Another 15 people were in grave condition in the city's hospitals.

Officials said the bottles with the lotion were clearly marked with warnings that they weren't for internal use. Russia's top investigative agency has opened a probe into the incident.

Poisonings with surrogate alcohol are a regular occurrence in Russia, but the Irkutsk case was one of the deadliest such incident in years.