Speaking on the fourth anniversary of the start of the conflict with Ukraine, Russia's President Vladimir Putin said Moscow's opponents had failed to achieve a "strategic defeat" on the battlefield and were now resorting to what he described as sabotage, strikes on infrastructure and assassination attempts. He warned that Russia's adversaries would "regret it" if they pushed too far.

Putin also suggested that Russian energy pipelines under the Black Sea could be targeted. He instructed officials to strengthen anti-terrorist protection of key facilities and public spaces, and to introduce additional security measures where necessary.

Kyiv has previously targeted Russian oil depots, refineries and ports. Ukraine has not immediately responded to Putin's latest remarks.