A wave of poisoning from methanol-tainted alcohol that has left at least 20 dead in the Czech Republic has spread to neighbouring countries, sending four to hospital in Slovakia.
The four were hospitalised on Sunday after drinking a bottle of Czech-made plum brandy ordered over the Internet.
Meanwhile in Poland, which on Sunday banned the sale of all Czech-made alcohol except for beer and wine, five deaths have been recorded in the past two weeks, though they were not necessarily linked.
"At the moment, we register 20 dead with confirmed methanol poisoning," Czech police spokeswoman Stepanka Zatloukalova told AFP, while local media said about 40 people were in hospital.
A health ministry analysis showed most of those affected had drunk one of two types of tainted liquor - vodka or a local rum dubbed "tuzemak".
The Czech Association of Spirits Producers and Importers meanwhile said it estimated the bootleg liquor sold on the black market "made up 20 percent of total Czech alcohol consumption."
On Friday, the Czech health ministry imposed a blanket ban on sales of spirits with over 20 percent alcohol content for the first time in the history of the nation of 10.5 million that has the world's second highest adult alcohol intake after Moldova.
The ban could last for months, Health Minister Leos Heger said.
Slovak authorities however merely warned the nation's 5.4 million citizens not to buy Czech spirits via the Internet.
Czech police have raided thousands of bars, restaurants and shops since the spirits ban was imposed and have so far charged 23 people in connection with the poisonings.
"We expect the number will grow as detained people are questioned," police spokeswoman Zatloukalova said.
Among those detained was a supplier whose plum brandy allegedly poisoned the four hospitalised Slovaks and at least one Czech.
The Slovaks had bought liquor for a 50th birthday party via the Internet and received it in plastic bottles, Slovak media reported.
In Poland Piotr Burda, head of the national toxicology centre, told AFP, "Over a 15-day period we registered nine cases of intoxication from bootleg liquor. Five people died."
But he added there was nothing to suggest the deaths could be linked to bootlegged Czech spirits.
"In Poland, the problem is above all alcohol substitutes consumed by alcoholics," he said, indicating radiator fluid and cleaning products.
In accordance with rules set by the European Union, Poland in 2010 struck down restrictions on the methanol content in cosmetic or chemical products including eau de Cologne perfume, radiator fluid and cleaning products.
According to Burda, the number of alcohol-related deaths in the country of 38.2 million has soared since the change. Over the course of six months to March 2012, more than 80 cases were registered, averaging eight to 10 per month, he added.
Czech police are still looking for the primary source of the poisonings and investigating all versions despite speculations over traces leading to Poland or to a single source.
"We can neither deny nor confirm that there's a single source - we simply don't know this at the moment," said Zatloukalova.
Irena Kolouchova from the Institute of Chemical Technology in Prague told the CT24 news channel she suspected the poisonings were caused by accident rather than on purpose.
"I can't imagine anyone knowing the toxic effects of methanol could add this substance to a spirit with the knowledge it can threaten people's lives," she said.