Russia's defense ministry has released the first video showing an underwater test of its Poseidon nuclear-powered drone.
The clip, released on Wednesday, came shortly after President Vladimir Putin's state-of-the-nation address.
Putin said the tests of the Poseidon have been conducted successfully and the first submarine equipped to carry it will be commissioned later this year.
He first mentioned the weapon early last year, saying it cannot be intercepted and can carry a nuclear warhead to target aircraft carrier groups or coastal areas.
Also in Wednesday's speech, Putin said he hopes to mend ties with the U.S. and remains open for arms control talks with Washington.