Russian President Vladimir Putin says modernized strategic bombers will boost the nation's military power.

Speaking on a visit to an aircraft-making plant in Kazan Thursday, Putin said the revamped version of the Soviet-designed Tu-160 bomber features new engines and avionics that would significantly enhance its capability.

The Russian leader attended the signing of a 160-billion-ruble (about $2.9-billion) contract that will see the delivery of 10 such planes to the Russian air force.

He said the upgraded bomber is a "serious step in the development of high-tech industries and strengthening the nation's defense capabilities."

The four-engine supersonic bomber developed in the 1980s is the largest combat plane in the world. During Russia's campaign in Syria, the military used the Tu-160s to launch log-range cruise missiles at militant targets.