Prime Minister Tayyip Erdogan signalled on Monday that Turkey was not prepared to compromise further on the conditions for the opening of its European Union entry talks. "We have protected and are continuing to protect our stance (on the talks), which is appropriate to Turkey's national interests and political principles," Erdogan told a gathering of his ruling AK Party to loud applause. Ankara is due to start negotiations on Monday but Austria has plunged the launch into doubt by insisting that Turkey be offered an alternative to full membership, Reuters reported. Separately, foreign ministry spokesman Namik Tan told reporters that Turkey rejected any proposed changes to the European Union framework agreement.