US denies involvement in Kremlin drone attack and says Moscow lacks strength to mount large attacks – as it happened

After Moscow accuses US of being behind Kremlin drone attack, White House says: We had nothing to do with this'. This live blog is closed

Here is more on the oil refinery attack from Tass and Reuters.

Part of an oil refinery in southern Russia is on fire after it was hit by a drone attack, Tass news agency cited local emergency services as saying early on Thursday.

Tass said the incident occurred at the Ilsky refinery near the Black Sea port of Novorossiysk. It cited a source as saying a fuel reservoir was on fire but gave no details.

Ukraine rarely claims responsibility for what Moscow says are frequent drone strikes against infrastructure and military targets, particularly in regions close to Russia.

Last June the Novoshakhtinsk oil refinery in Russia's Rostov region, bordering Ukraine, suspended operations after two unmanned aerial vehicles attacked its facilities.