Armenian foreign minister, Edouard Nalbandian, front left, and Turkish foreign minister, Ahmet Davutoglu, front right, shake hands while Swiss foreign minister, Micheline Calmy-Rey, French foreign minister, Bernard Kouchner, and US Secretary of State, Hillary Rodham Clinton, back from left, applaude during the signing ceremony of the protocols and statements between Armenia and Turkey, at the University of Zurich in Zurich, Switzerland, Saturday, Oct. 10, 2009.  [Agencies]

ZURICH: Turkey and Armenia signed a landmark agreement Saturday to establish diplomatic relations and open their sealed border after decades of enmity, as US Secretary of State Hillary Rodham Clinton helped the two sides clear a last-minute snag.

The contentious issue of whether the killing of up to 1.5 million Armenians during the final days of the Ottoman Empire amounted to genocide is only hinted at in the agreement.

"There were several times when I said to all of the parties involved that this is too important," Clinton said. "This has to be seen through. We have come too far. All of the work that has gone into the protocols should not be walked away from."

The Turkish and Armenian foreign ministers signed the accord in the Swiss city of Zurich after a dispute over the final statements they would make. In the end, the signing took place about three hours later than scheduled and there were no spoken statements.

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Clinton and mediators from Switzerland intervened to help broker a solution, US officials said on condition of anonymity, in keeping with State Department regulations. Better ties between Turkey, a regional heavyweight, and landlocked Armenia have been a priority for President Barack Obama, and Clinton had flown to Switzerland to witness the signing, not help close the deal.

Clintontold reporters traveling later on the plane with her to London that both sides had problems with the other's prepared statement and that the Armenian foreign minister had to call his president several times.

She said it became important just to approve the accord and not have the sides make speeches that could be interpreted as putting legal conditions on the document. She told each country that could be done later, "but let the protocols be the statement because that was what we were there to sign."

The accord is expected to win ratification from both nations' parliaments and could lead to a reopening of their border within two months. It has been closed for 16 years.

But nationalists on both sides are still seeking to derail implementation of the deal.

UN Secretary-General Ban Ki-moon called the signing a "historic decision" that "constitutes a milestone toward the establishment of good neighborly relations," spokeswoman Michele Montas said in New York.

American officials said Clinton; the top US diplomat for Europe, Philip Gordon; and Swiss Foreign Minister Micheline Calmy-Rey were engaged in furious high-stakes shuttle diplomacy with the Turkish and Armenian delegations to resolve the differences.

Diplomats said the Armenians were concerned about wording in the Turkish statement that was to be made after the signing ceremony at University of Zurich and had expressed those concerns "at the last minute" before the scheduled signing ceremony.