MOSCOW, July 29 (RIA Novosti) - The deployment of a Russian military base in southern Kyrgyzstan has been coordinated with Kyrgyz authorities, an aide to the Russian president said on Wednesday.

"Everything has been agreed, in principle," Sergei Prikhodko said on the eve of an informal summit of the Collective Security Treaty Organization (CSTO), to be held in Kyrgyzstan on Friday.

The post-Soviet CSTO security bloc comprises Armenia, Belarus, Kazakhstan, Kyrgyzstan, Russia, Uzbekistan and Tajikistan.

Russia earlier offered to deploy a battalion-sized unit as part of the CSTO rapid reaction force in the Batkenskaya region of Kyrgyzstan.

"In essence, this is not a Russian base. These are efforts in line with CSTO plans to set up a joint rapid reaction force," Prikhodko said.

Russia's security strategy until 2020, recently approved by President Dmitry Medvedev, envisions the CSTO as "a key mechanism to counter regional military challenges and threats."

The leaders of the post-Soviet security bloc signed on June 14 an agreement on creating a joint rapid reaction force, which will comprise large military units from five countries - Kazakhstan, Kyrgyzstan, Russia, Uzbekistan and Tajikistan.

Russia already operates an airbase in the city of Kant, some 20 kilometers (12 miles) outside the Kyrgyz capital, Bishkek.

Some 250 Russian officers and 150 enlisted personnel from Russia's 5th Air Army are deployed at the base, as well as Su-25 Frogfoot strike aircraft and Mi-8 transport helicopters.

Prikhodko said Moscow was not concerned about the presence of a U.S. transit center in Kyrgyzstan to support an international contingent which is fighting Taliban militants in Afghanistan.

Kyrgyz President Kurmanbek Bakiyev signed on July 7 a law allowing the U.S. to continue using its Manas airbase for the transit of troops and supplies to Afghanistan.

"If the operation of the center is carried out in line with its stated mandate, we will have no formal cause for concern," the Kremlin official said, adding that if the mandate is violated, Kyrgyzstan will have to provide explanations to other CSTO members.