ISTANBUL — Turkey and Armenia, whose century of hostilities constitutes one of the world's most enduring and acrimonious international rivalries, have agreed to establish diplomatic relations, the two countries announced Monday.
In a breakthrough that came after a year of tiny steps across a still-sealed border and furtive bilateral talks in Switzerland, the foreign ministries of the two countries said that they would begin talks aimed at producing a formal agreement.
The joint statement said they had agreed "to start political negotiations" but did not touch on when or how some of their more intractable disputes would be addressed, starting with the killing of more than 1 million Armenians by the Ottoman Turk government from 1915 to 1918, which the Turkish government has denied was genocide.
The two countries have never had diplomatic relations, and their border has been closed since 1993, when Armenia and Azerbaijan, both former Soviet republics, went to war over the enclave of Nagorno-Karabakh.
Turkey supported Azerbaijan in the dispute, but Russia's military action in Georgia last year shifted the security calculus in the region. After the war in Georgia, Turkey sought to improve ties with its neighbors in the Caucasus, and Armenia elected a new government interested in reciprocating.
Both countries hope an eventual opening of the border will benefit their struggling economies.
For Turkey, better relations with Armenia could improve its chances for admission to the European Union, where the genocide issue remains one of the main obstacles, and remove a bone of contention over the same issue with the United States, which has a large Armenian community.
The Swiss-mediated talks began last year, keeping a low profile to avoid exciting nationalist antagonism in both countries. Armenia's insistence that border and trade relations be normalized before any discussion of genocide began helped push the most contentious issue to the back burner.
Last September, President Abdullah Gul of Turkey attended a Turkey-Armenia soccer match in Yerevan, the Armenian capital, the first visit by a Turkish leader in the two nations' history.
The symbolic gesture, dubbed soccer diplomacy, was widely opposed in both countries, where bitter ethnic enmity commands large majorities.
The next round of talks is scheduled to last six weeks, ending about the time of a World Cup match between Turkey and Armenia in Istanbul. President Serge Sargsyan of Armenia is invited to attend.