Russia said Thursday it had successfully test-fired an upgraded version of a nuclear-capable missile that entered into service in the Soviet era and had been due to be scrapped.

A defence ministry spokesman said the RS-12M Topol had hit its target at a test range that Russia leases from Kazakhstan after it was fired from the Kapustin Yar military site near the Caspian Sea.

"The exercise head of the rocket hit the hypothetical target on the Sary-Shagan test site in Kazakhstan," spokesman Igor Yegorov told the Interfax news agency.

Russia is the only country in the world to still test-launch intercontinental ballistic missiles.

Most of the launches are performed to either ensure the safety of Russia's ageing arsenal or to test new rockets that could penetrate a missile defence system now gradually being deployed by NATO in Europe.

Yegorov said the launch was designed to test improvements meant to keep the RS-12M Topol -- a three-stage ballistic missile that has provided the backbone of Russian defences since Soviet times -- in service for years to come.

"The purpose of this launch was to confirm the stability of the main flight parameters of this class of rocket during extended service," Yegorov said.

Yegorov said the first RS-12M Topol entered into service 25 years ago.