The sound of Kremlin sabre-rattling is being clearly heard in Kyiv as 150,000 Russian troops, hundreds of tanks and planes perform military exercises close to the Ukrainian border. Forces in Russia’s Western and Central sectors have been placed on “combat ready” alert, and the sectors’ air wings have been mobilised to fly patrols.

Ukraine has warned Russia that any straying over the border during the manoeuvres will be considered as an act of agression, and warnings over Russian intervention in Ukraine have echoed in several Western capitals. Kyiv has also said any Russian troop movements from Moscow’s Crimean naval complex will be considered an aggressive act as well.

Ukraine has called in Russia’s acting envoy for consultations over the seizing by armed men of the Crimean parliament, and says it wants urgent talks with Moscow.

Kyiv has ordered the army and Interior Ministry forces to mobilise and maintain a state of readiness.