At least twenty-five residents of the Siberian city of Irkutsk have died after drinking bath oil, hoping it would give them the same sensation as alcohol, Russian investigators said today.

Use of counterfeit or surrogate alcohol is rife in Russia's regions, where two years of economic pain have pushed more people below the poverty line, though the death toll from this latest incident is unusually high.

Investigators in Irkutsk, a city of around 600,000 people around 2,600 miles (4184.29 km) east of Moscow, said in a statement they had detained two people suspected of distributing the bath oil.

The product had a warning on its label saying it should not be swallowed, but investigators said people had ignored that and consumed it as if it was alcohol. The bath oil contained methylated spirit, they said.

It was unclear whether those selling the product were marketing it as a cheaper substitute for alcoholic spirits such as vodka.

"Forty-two people have been admitted to medical institutions of whom 25 have died," investigators said in the statement.

"Investigators and the police are conducting searches at markets where the liquid was first obtained. More than 100 points of sale have been identified."

The Interfax news agency said the death toll had been revised up to 33 since the release of the initial statement.

Prime Minister Dmitry Medvedev told a government meeting he wanted to look at banning products that could cause so many deaths and said the country's criminal code was being amended to toughen the punishment for people caught selling them.

Investigators, who said they had opened a criminal case into the poisonings, said they had confiscated more than 2,000 litres of spirit.

Stanislav Zubovsky, a local prosecutor, told the Interfax news agency that police were continuing to search residential areas and that "the number (of deaths) will increase further."

Corrected at 1pm: A previous version of this article mistakenly cited Irkutsk's population as being 6,000.