The Turkish and Greek Cypriot delegations have failed to agree on maps for new borders on the divided island state, each slamming the other's proposals as "unacceptable," Turkey's foreign minister said Saturday, after peace talks stalled. A week of U.N.-brokered talks in Geneva between Greek Cypriot President Nicos Anastasiades and Turkish Cypriot leader Mustafa Akıncı had sparked optimism that an agreement to reunify the island could be at hand. For the first time since Cyprus was divided, each side unveiled their vision on Wednesday of how they saw the borders of a reunified country.

Akıncı "strongly stressed that the Greek offer could not be taken seriously [and] that no Turkish Cypriot would accept this map," Çavuşoğlu told reporters in Ankara. "The same goes for us," he added.

The thorny issue centers on how the boundaries are redrawn, including around the once Greek Cypriot town of Morphou on the northern coast.

Anastasiades has warned that there can be no deal without a full return of Morphou, while some in the Turkish Cypriot camp have declared its return a non-starter.

The maps swapped Wednesday will not be disclosed publicly, with the U.N. hoping that both sides will eventually agree on a compromised version. Turkish and Greek Cypriots exchanged maps on proposed territorial boundaries Wednesday and the documents were sealed in a U.N. vault.

Reunification talks resumed last May with both sides repeatedly expressing optimism over a possible solution. Once a final agreement is reached, it would be put up for a referendum to be voted on by the two Cypriot communities. Akıncı has said a reunification vote could be held in mid-2017, if an agreement is indeed reached in Geneva.

Meanwhile, Reuters reported yesterday that a working group due to convene on Jan. 18 to hammer out security arrangements for a post-settlement Cyprus will meet for two to three days only, followed by another round of high-level talks, a source close to the Turkish Cypriot side said.

Talks in Geneva last week failed to produce a breakthrough in a conflict spanning decades, though the three countries which are stakeholders in Cyprus - Britain, Greece and Turkey - agreed to set up the working group to look at security arrangements after these turned out to be a major sticking point.