The statement by Russian Lt. Gen. Anatoly Zhikharev appears to contradict claims earlier this year by Deputy Prime Minister Dmitry Rogozin, RIA Novosti reported.
A prototype of the bomber, known as PAK-DA, is scheduled to be ready by 2020, Zhikharev said.
Hypersonic speeds are considered those of at least Mach 5 -- about 3,800 mph. Such speeds can generally be generated only by ramjets or scramjets.
In August, Rogozin reiterated that Russia needed to develop a hypersonic aircraft, saying "we are moving in that direction and are not falling behind the Americans. We will use this technology when developing a new bomber."
Russian President Vladimir Putin ordered development of the PAK-DA in June as a long-range bomber.
In May, Rogozin called on Russia's defense industry to develop weapons to counter U.S. development of hypersonic aircraft and weaponry.