Armenia has signed a memorandum of cooperation with the Eurasian Economic Commission, which oversees the integration of former Soviet republics around the Russia-led Customs Union.
The document was signed in Yerevan on November 6 during talks between Armenian Prime Minister Tigran Sarkisian and visiting senior officials from the Customs Union's member states -- Russia, Belarus, and Kazakhstan.
The memorandum was approved by presidents of the three member states at a summit held in Minsk last month.
Armenia announced its intention to join the Customs Union in September.
EU Enlargement Commissioner Stefan Fuele has said that Yerevan cannot sign an EU Association Agreement at a summit in Vilnius later this month if it also intends to join the Customs Union.
Moscow has said the union will be widened into a Eurasian economic union, modeled after the European Union, by 2015.