(adds denial of Lithuanian import ban)

WARSAW, Dec 2 (Reuters) - Poland"e;s veterinary service has culled 4,200 turkeys following an outbreak of H5N1 bird flu on two poultry farms northwest of Warsaw, officials said on Sunday.

"The turkeys were gassed on Saturday night and the destruction of their carcasses is due to end on Sunday," PAP news agency reported district crisis-management chief Hilary Januszcyzk as saying.

He added that no new cases had been detected so far.

Two turkey farms in the Plock area, some 80 km (50 miles) northwest of Warsaw, were cordoned off after the outbreak was discovered and routine precautions were carried out.

Poland"e;s chief veterinary officer said Lithuania had not banned Polish poultry imports.

"I was told by the head of Lithuania"e;s Food and Veterinary Service, Kazimieras Lukauskas, that no such ban had been introduced," Ewa Lech told PAP news agency.

"They are waiting for a decision from the European Commission and will abide by the principles accepted in the EU."

Earlier, Polish Agriculture Minister Marek Sawicki expressed surprise at reports that Lithuania had banned poultry imports from Poland following Saturday"e;s outbreak.

Poland and Lithuania have been EU members since May 2004.

Sawicki said the poultry-farm owners whose stocks had been destroyed would be compensated at current retail prices.

Migrating ducks, geese or swans most likely brought the bird flu virus to Poland, officials have said. Poland"e;s previous bird flu outbreak was in wild swans in the northern city of Torun in 2006.

According to the World Health Organisation, the virus has caused more than 200 deaths in humans globally since 2003. None have been reported in Poland. (Reporting by Rob Strybel; editing by Elizabeth Piper)