Turkish Cypriot foreign minister Kudret Ozersay has announced his resignation in protest at the nationalist prime minister's decision to reopen the Greek Cypriot resort of Varosha, a sealed-off ghost town since 1974, just days before a presidential election.
Ozersay's People's Party, the third largest in the breakaway Turkish Cypriot state's parliament, also pulled out of the governing coalition, depriving it of its majority, he announced late on Tuesday.
Speaking after Tuesday talks with Turkish President Recep Tayyip Erdogan, Turkish Cypriot prime minister Ersin Tatar announced that the coastal section of Varosha would reopen on Thursday.
The move was condemned by Tatar's opponents as a ploy to shore up his nationalist base ahead of Sunday's election and an act of interference by Ankara in Turkish Cypriot affairs.
"It is unacceptable that Tatar ignored the will of his coalition partner and the Turkish Cypriot people," Ozersay said.
Both Tatar and Ozersay are challenging dovish incumbent Mustafa Akinci in Sunday's election, which was delayed from April by the coronavirus pandemic.
Akinci too strongly criticised the announcement from Ankara, calling it a "shame for our democracy" and "interference in our elections".
The president, who is the only Turkish Cypriot official to have international status as leader of the island's minority community, has long had difficult relations with Ankara, the only government which recognises the breakaway Turkish Cypriot state.
In February, Turkey accused him of being "dishonest" after he described the prospect of annexation by Ankara as horrible.
Akinci represents the Turkish Cypriot side in currently dormant UN-backed talks on ending the island's decades-long division.
- Haunt of celebrities -
The return of Varosha to its Greek Cypriot former inhabitants has been a central part of every UN-backed proposal to reunify the island.
In its heyday in the early 1970s, the resort was a favoured haunt of celebrities including Elizabeth Taylor and Richard Burton.
But the Turkish invasion of 1974, launched in response to a Greek Cypriot coup seeking to annex the whole island to Greece, emptied the resort district and the wider city of Famagusta of its Greek Cypriot residents and property owners.
It has been sealed off by the Turkish army ever since.
The Turkish Cypriots have long considered unilaterally reopening Varosha as a means of jump-starting talks.
But they have previously always held back in the face of opposition from the island's internationally recognised government and the international community.
Cyprus government spokesman Kyriakos Kousios described the move as "a pre-election stunt created in Ankara, on the eve of an election for a new Turkish Cypriot leader".
EU foreign policy chief Josep Borrell said the bloc was "very concerned" about Tuesday's announcement and stressed the "urgency of restoring confidence and not of creating greater divisions."
Akinci is the favourite going into Sunday's election, which is likely to be decided in a second-round runoff between himself and Tatar.
Former prime minister Tufan Erhurman of the centre-left Turkish Republican Party, the second largest in parliament, is also standing, alongside minor party candidates and independents.