Kyrgyzstan has become a full-fledged member of the Russian-led Eurasian Economic Union (EES) after it formally abolished customs controls along its border with Kazakhstan.
Kyrgyz President Almazbek Atambaev and Kazakh President Nursultan Nazarbaev took part in a ceremony marking the development on August 12 via video link from a resort where the two have been meeting near Lake Issyk-Kul in northern Kyrgyzstan.
"Kazakhs and Kyrgyz are brotherly nations and therefore there should be no boundaries, no barriers between them," said Atambaev, whose country joins fellow former Soviet republics Russia, Kazakhstan, Belarus, and Armenia in the grouping.
Nazarbaev said Kazakhstan wishes "peace, stability and prosperity to the nation of Kyrgyzstan" and "will continue supporting its brotherly nation by all possible means."
Customs controls at eight checkpoints along the Kyrgyz-Kazakh border were lifted on August 12.
Kyrgyz Prime Minister Temir Sariev attended the ceremony at the Ak-Jol checkpoint along the frontier between his Central Asian nation and its much bigger, energy-rich northern neighbor, Kazakhstan.
He told journalists that membership in the EES will give Kyrgyzstan many advantages.
"Our citizens now have the opportunity for free travel to EES member states and free transportation of goods, services, and capital across the border," Sariev said.
The Eurasian Economic Union was built on the foundation of a customs union between Russia, Belarus, and Kazakhstan, and formally came into existence in January.
It aims to create a single market for the free movement of goods and services over a total population of more than 180 million people, similar to the 28-nation European Union.
It is one of a handful of security and economic alliances that Russian President Vladimir Putin has used in an attempt to bolster Moscow's influence in the former Soviet Union and counter the EU and NATO.
Nazarbaev was the initiator of the idea of a trade bloc, but he and Belarusian President Alyaksandr Lukashenka -- wary of ceding any sovereignty to Russia -- have stressed that it should stay out of politics.
Russia pushed hard for Ukraine to join the bloc, but opponents saw it as an attempt by Moscow to increase its influence and essentially reconstitute the Soviet Union.
The issue was a key factor in the upheaval in Ukraine, where President Viktor Yanukovych was ousted in February 2014 following months of pro-European protests sparked by his abrupt decision to scrap plans for a landmark pact with the European Union and build up economic ties with Russia.
The agreement on Kyrgyzstan's accession to the EES was signed in December at a session of the Supreme Eurasian Economic Council in Moscow.
Protocols to the agreement were signed by the EES member states in May.
Kyrgyzstan borders only one EES member state: Kazakhstan.