The refusal of Ukraine and NATO powers to recognise Moscow's authority over Crimea represents a "systemic threat" for Russia, former Russian president Dmitry Medvedev said on Sunday.
Russia annexed the Black Sea peninsula of Crimea from Ukraine in 2014 after a pro-Moscow president in Kyiv was toppled amid mass street protests. Moscow then also backed pro-Russian armed separatists in the Donbas region of eastern Ukraine.
"If any other state, be it Ukraine or NATO countries, believes that Crimea is not Russian, then this is a systemic threat for us," Medvedev told World War Two veterans, the Interfax news agency reported.
"This is a direct and an explicit threat, especially given what had happened to Crimea. Crimea returned to Russia," said Medvedev, who now serves as deputy chairman of the Russian Security Council.
His comments were aired a day after a Ukrainian official suggested that Crimea, which most of the world still recognises as part of Ukraine, could be a target for U.S.-made HIMARS missiles, recently deployed by Kyiv as it battles Russian forces.
Vadym Skibitskyi, an official at Ukrainian military intelligence, was asked on Saturday in a televised interview if HIMARS could be used on targets in Crimea.
He said Russia had carried out strikes on Ukrainian territory from Crimea and the Black Sea and so these were also justified targets.
Crimea is of particular strategic importance to Russia as it includes the headquarters of its Black Sea fleet at Sevastopol.
(Reporting by Reuters; Editing by Guy Faulconbridge and Gareth Jones)