Col. Gen. Vladimir Popovkin, commander of the Russian Space Troops -- the country's military space agency -- was quoted by the Argumenty i Fakty weekly as saying launches from Baikonur are cheaper than ones from cosmodromes in Russia.
"The closer to the equator, the less fuel is needed to put a kilogram of payload into orbit," Popovkin said.
Space vehicles for communications, early warning of missile attacks and reconnaissance carry a lot of weight and require a considerable amount of fuel to be placed into orbit. The standard Soyuz booster would not be able to lift such payloads from the Plesetsk cosmodrome in northern Russia, Popovkin said.
"At present, Baikonur is vital for us," he added.
The Baikonur cosmodrome -- 330 miles to the southwest of the Kazakh capital, Astana -- is leased by Russia for $115 million annually and the lease is valid until 2050. The cosmodrome marked its 50th anniversary last Thursday.