Avril Haines says Russian leader could see prospect of Ukraine defeat as existential threat, potentially triggering escalation

Vladimir Putin could view the prospect of defeat in Ukraine as an existential threat to his regime, potentially triggering his resort to using a nuclear weapon, the top US intelligence official has warned.

The warning on Tuesday came in an assessment from intelligence chiefs briefing the Senate on worldwide threats. The prediction for Ukraine was a long, gruelling war of attrition, which could lead to increasingly volatile acts of escalation from Putin, including full mobilisation, the imposition of martial law, and – if the Russian leader felt the war was going against him, endangering his position in Moscow – even the use of a nuclear warhead.