Russian President Vladimir Putin said an attack by his forces on the eastern Ukrainian city of Dnipro on Thursday morning was carried out using "a new conventional intermediate-range missile".
He said that the missile, codenamed Oreshnik, was a response to Ukraine's use of US and UK-supplied long-range weaponry towards targets inside Russia.
Putin also suggested Russia could attack military facilities of those countries which allowed their weapons to be used for this purpose.
The US and the UK authorised the use of US ATACMS and UK-supplied Storm Shadow missiles this week, in a major change of policy.