A prototype hypersonic missile designed for use aboard Russia’s new Su-57 fifth-generation stealth fighter has been created, a defence sector source had told Russian media.

The source described the missile as a small, air-to-surface weapon designed to be carried inside the plane’s fuselage, and said it has yet to be tested aboard the plane.

No other details about the weapon’s characteristics or who developed it were made available, and the reports have yet to be commented on by anyone at UAC, Sukhoi or the military.