The statement came ahead of the April 24 commemoration of mass killings of Armenians by Ottoman Turks in 1915. The two countries are engaged in high-level talks to restore ties.
"The two parties have achieved tangible progress and mutual understanding in this process and they have agreed on a comprehensive framework for the normalisation of their bilateral relations," said a statement issued by the foreign ministries of both countries.
Switzerland has been acting as a mediator between Turkey and Armenia.
The agreement is sure to upset Turkey's traditional ally Azerbaijan, putting at risk gas deals Ankara and the European Union are trying to seal with the major natural gas producer to boost exports to Europe.
The statement did not say how they would tackle a bitter dispute over Ottoman-era killings of ethnic Armenians, nor if Ankara and Yerevan had reached an agreement to open the border.
The diplomatic ouverture comes a day before Armenia commemorates the anniversary of the 1915 killings of Armenians by Ottoman Turks, which it claims amounted to genocide.
Turkey strongly denies Armenian charges, and says many were killed on both sides.
"We don't want to make any more further comment than what is said in the statement. We will continue with our policy of silent diplomacy. The time has not come yet to make announcements on specifics nor on timelines," said a Foreign Ministry source.
US President Barack Obama, during a visit to Turkey earlier this month, called on Turkey and Armenia to make progress on the negotiations.
The United States welcomed the statement and urged Ankara and Yerevan to normalise ties "within a reasonable timeframe."
"We urge Armenia and Turkey to proceed according to the agreed framework and roadmap," acting State Department spokesman Robert Wood said in a statement. Turkey closed its border with Armenia in 1993 in support of Azerbaijan, which was fighting Armenian-backed separatists in the breakaway mountain region of Nagorno-Karabakh.
A breakthrough between Turkey and Armenia could help to shore up stability in the volatile, oil-rich Caucasus.
(EurActiv with Reuters.)
