A planned peace agreement between Turkey and Armenia to end a century of enmity hit a last minute snag today over disagreements with statements to be read at the historic ceremony.
U.S. officials sought to help smooth over disagreements with Armenian foreign minister Edward Nalbandian over the statements, while Turkish Foreign Minister Ahmet Davutoglu waited at the venue along with international dignataries.
U.S. Secretary of State Hillary Clinton returned to a Zurich hotel so U.S. officials could meet Nalbandian, whose delegation had not left for the venue where the deal was due to be signed at 5 p.m (1500 GMT).
"We're helping facilitate the two sides come to agreement on statements that are going to come out," U.S. State Department spokesman Ian Kelly told reporters. "There's not a breakdown."
A U.S. official said a new version of the Turkish statement had been brought to the hotel.
The deal to normalise ties and reopen the border has faced fierce opposition from nationalists on both sides and a Armenian diaspora which insists Turkey acknowledge the killings of up to 1.5 million Armenians by Ottoman forces in World War One as genocide.
A decades-old dispute between Turkey's ally Azerbaijan and Armenia over the disputed enclave of Nagorno-Karabakh had hung over the deal after talks between Azeri and Armenian leaders over the region ended without result on Friday.
An accord would boost U.S. ally Turkey's diplomatic clout in the volatile South Caucasus, a transit corridor for oil and gas to the West. U.S. Secretary of State Hillary Clinton and other dignitaries were to attend the signing.
But disagreements over the Ottoman killings, which Yerevan calls genocide, a term Ankara rejects, and a decades old dispute between Turkey's ally Azerbaijan and Armenia over Nagorno-Karabakh hang over the settlement.
Under U.S. and EU pressure, officials from European Union candidate Turkey and former Soviet republic Armenia said they would sign the Swiss-mediated accord, which sets a timetable for restoring diplomatic ties and opening their border.
It must then be approved by their parliaments in the face of nationalist opposition and the powerful Armenian diaspora.