US and Europe fear escalation of Russian hybrid warfare amid Ukraine missile attacks

Officials incredibly concerned' as Moscow vows response to Kyiv's use of US-made missiles on targets inside Russia

• Atacms: what are the missiles Ukraine has fired into Russia for first time?

The US state department said it was incredibly" concerned about Russia's campaign of hybrid warfare against the west, amid fears it will escalate following Ukraine's first use of US-made long-range missiles on targets inside Russia, after the Biden administration lifted restrictions on their use.

Russia has promised an appropriate" response to the new policy, and has engaged in nuclear sabre-rattling by changing its nuclear doctrine in recent days. However, western officials believe the thrust of the Russian response may come not on the battlefield in Ukraine but elsewhere in the world.