Kyiv celebrates independence from the Soviet Union as the long war with Russia has reached a dramatic moment, with Ukrainian forces mounting an incursion in Russia’s Kursk region and Moscow eyeing more east Ukrainian towns.

Zelensky published a video from a deserted, forested area in the Sumy region, which he visited earlier this week, saying it was a “few kilometres” from where Ukrainian forces shocked the world on Aug 6 by crossing into Russia.

The war-time leader said Kyiv “surprises once again” and vowed that Russia “will know what retribution is”.

By launching its 2022 invasion, he said, “Russia was seeking one thing: to destroy us. Instead, today we celebrate the 33rd independence day of Ukraine. And what the enemy brought to our land has now returned to its home.

“Anyone who wants to sow evil on our land will reap its fruit on their territory,” he added. “This is not a prediction, not gloating, not blind revenge. It is justice”.

Zelensky called Russian president Vladimir Putin a “sick old man from Red Square who constantly threatens everyone with the red button”.

Ukraine’s Kursk incursion has rattled Moscow, but not slowed Russia’s advance in eastern Ukraine.