The Russians have been accused of breaking a long-held ban on weapons in space by firing a projectile from a satellite.
The US and the UK have called out their rivals' actions, saying the firing "threaten the peaceful use of space".
In a statement, Air Vice-Marshal Harvey Smyth, head of the UK's space directorate, said: "We are concerned by the manner in which Russia tested one of its satellites by launching a projectile with the characteristics of a weapon.
"Actions like this threaten the peaceful use of space and risk causing debris that could pose a threat to satellites and the space systems on which the world depends.