The head of Turkey's governing party sharply criticised Turkish Cypriot leader Rauf Denktash in a television interview, urging him to negotiate to reunite the island.
"I'm not in favour of the continuation of the policy that has been maintained in Cyprus over the past 30-40 years," said Recep Tayyip Erdogan, leader of the Justice and Development Party (AKP).
His unprecedented comments reflect Turkey's strong desire to get a deal on Cyprus, which could boost its own campaign to join the European Union.
The EU has told Turkey that membership talks will start without delay if a review in late 2004 finds it has carried out the reforms deemed necessary.
Mr Erdogan called on Mr Denktash to negotiate on the basis of United Nations proposals that would mean Cyprus being demilitarised and divided into cantons like Switzerland.
A close adviser to Mr Denktash dismissed Mr Erdogan's remarks as the opinion of only one individual.
The adviser, former Turkish Foreign Minister Momtaz Soysal, added that in Turkey, the president and the army - not just the government - played a role in forming policy.
Turkey's powerful army has traditionally supported the division of Cyprus - but the BBC's Tabitha Morgan in Cyprus says many Turkish Cypriots will welcome Mr Erdogan's intervention.
EU membership
The European Union, which last month invited Cyprus to join, has urged Greek and Turkish Cypriots to reach agreement on the island by the end of February.
"
Let's leave confidence aside here - if we find this negotiable, let's negotiate
"
Recep Tayyip Erdogan
If the two sides do not settle their differences by then, EU membership will, in effect, cover only the Greek Cypriot-run part of the island.
The two sides failed to reach an agreement on the sidelines of the EU summit last month, which Mr Denktash was too ill to attend.
Mr Erdogan has endorsed UN plans for the reunification of Cyprus but Mr Denktash has said he is unwilling to negotiate with the Greek Cypriot Government.
The Turkish leader insisted he do so.
"He says he can't trust the other side. Let's leave confidence aside here," Mr Erdogan said. "If we find this negotiable, let's negotiate."
Welcome change
Cyprus has been divided for almost three decades, since Turkish troops invaded and occupied part of it in 1974 following an Athens-backed coup by Greek Cypriots.
Only Ankara recognises the Turkish Republic of Northern Cyprus, which was declared nearly 10 years later.
The Greek Cypriot Government welcomed the apparent change in Ankara's position.
"We are witnessing the beginning of the post-Denktash era," Greek Cypriot Foreign Minister Yiannakis Kassoulides said.
"The sooner [Mr] Denktash realises this, the better. If he does not, then the only thing left is for him to be forced to comply or to be sidelined," he added.
Mr Erdogan also commented on last week's protest by an estimated 30,000 Turkish Cypriots against Mr Denktash's hardline stance.
He said the public's view could not be brushed aside and he pressed Mr Denktash to return to the negotiations.
The Turkish Government usually supports the Turkish Cypriot leadership at every turn, but elements within the new government are deeply frustrated at what they see as Mr Denktash's obstinacy, the BBC's Istanbul correspondent Jonny Dymond says.
Re-election
Separately, Greek Cypriot President Glafcos Clerides said he might seek re-election next month in order to maintain momentum in negotiations.
Mr Clerides, 83, is coming to the end of his second five-year term as president and must announce by 17 January whether he will stand again.
"If a solution is found there will not be any reason for me to ask to continue as president of the Republic of Cyprus," Mr Clerides told the Reuters news agency on Thursday.
"If it is not [found], then it would be very unwise in the middle of the negotiations to walk out and give the matter to somebody else," he said.