Answer: Russia
Notes: Russia's Onyx supersonic cruise missile, known as the P-800 Onyx or Oniks, is set to become deadlier with a new target seeker. With speeds exceeding 3,000 km/h, it's tough to intercept. Operating at low altitudes, it's stealthy and versatile, targeting ships and ground objects. It boasts a range of up to 300 km and operates on a "shoot and forget" principle, needing minimal target data for successful strikes.
