Armenia and Turkey came to an agreement April 23 on a "roadmap" aimed at normalizing bilateral relations, which have been virtually non-existent following a bitter row over the massacre of ethnic Armenians in Turkey in the early 20th century.
Turkey says Armenia must end attempts to have the killings recognized as an act of genocide, and claims the deaths of an estimated 1.5 million Armenians at the end of the Ottoman period in 1915 were caused by civil unrest as the Empire collapsed. However, Armenia and a number of other countries say the killings were the first genocide of the 20th century.
"We welcome the steps by Armenian President Serzh Sargsyan aimed at normalizing the Armenian-Turkish relations without preconditions and within reasonable terms," the coalition parties said in a statement.
Armenia's coalition, formed in March 2008, unites the Republican Party of Armenia, Prosperous Armenia, Orinats Erkir (Country of Law) and the Armenian Revolutionary Federation (Dashnaktsutyun).
However, the Dashnaktsutyun party announced on Monday it was withdrawing from the coalition over the "roadmap" agreement with Turkey, which it called "unacceptable and condemnable."
The Armenian ruling coalition said in a statement it respected the position of Dashnaktsutyun and hoped to "cooperate on a broad range of issues of national and state interests."
The border between Armenia and Turkey was closed in 1993 on Ankara's initiative following fighting between Armenia and Turkey's ally, Azerbaijan, over Nagorny Karabakh. The disputed region has a majority Armenian population, but which is within Azerbaijan's borders. Turkey has said it wants talks with Armenia to take place in parallel to Armenian-Azerbaijani discussions on the future status of the region.