Prime Minister Tayyip Erdogan bluntly told the European Union on Friday it had no business meddling in Turkish domestic affairs as Turkey's decades-old campaign to join the wealthy bloc turned bitter.
"We are Turkey and we make our own decisions. Nobody should try to impose conditions on us concerning the EU," Erdogan told members of his ruling Justice and Development Party (AKP), a conservative movement with roots in political Islam.
Earlier the European Commission had criticised a delay by Turkey in adopting a new penal code because of a wrangle over whether it should also outlaw adultery.
"Nobody can interfere in the way our parliament works and its timing," Erdogan said.
But European Enlargement Commissioner Guenter Verheugen, who will publish a verdict on Turkey's EU candidacy on October 6, insisted Ankara must swiftly approve the revised penal code to prove it was a "state of law".
Turkish shares and the lira currency tumbled on Erdogan's unusually blunt remarks, reflecting investors' concerns the spat could influence the Commission's progress report, which will determine whether Ankara is ready for long-delayed entry talks.
The European Commission has a right and a duty to advise on and criticise reforms in would-be EU member states.
But European criticism of the pace and nature of the penal code reform, and particularly its comments on the wrangle over adultery, touched a raw nerve.
European Commission spokesman Jean-Christophe Filori earlier urged Ankara not to outlaw adultery.
"Such provisions would certainly cast doubts on the direction of Turkey's reform efforts and would risk complicating Turkey's European prospects," Filori said.
His boss Verheugen later took aim at the penal code delay.
"It is a very worrying development," Verheugen told reporters in the Belgian town of Leuven.
"I can only say it would be much better to have the new penal code adopted because this is the centrepiece of the question of whether Turkey meets the conditions of being a state of law," the German commissioner said.
The revised penal code bolsters women's rights and freedom of expression and increases penalties for such crimes as rape and "honour killings" - the murder of women by male relatives to protect the family name.
The government put the draft penal code on hold late on Thursday after the centre-left opposition blocked its efforts to include a clause banning adultery.
Erdogan says the ban will protect women and the family, but critics say it pushes Turkey closer to Islamic law-based states such as Saudi Arabia and further from the modern European model.