(Reuters) - President Volodymyr Zelenskiy urged the West to stop playing around with Russia and impose tougher sanctions on it to end its "senseless war" in Ukraine, adding that his country would remain independent, the only question was at what price.

Zelenskiy's criticism of the West has mounted in recent days as the European Union moves slowly towards a possible Russian oil embargo and as thousands of Russian troops try to encircle the two eastern cities of Sievierodonetsk and Lysychansk.

Three months into its invasion of Ukraine, Russia has abandoned its assault on the capital Kyiv and is trying to consolidate control of the industrial eastern Donbas region, where it has backed a separatist revolt since 2014.

Western military analysts see the battle for Sievierodonetsk and Lysychansk as a possible turning point in the war after a shift in momentum towards Russia following the surrender of Ukraine's garrison in Mariupol last week.

"Ukraine will always be an independent state and it won't be broken. The only question is what price our people will have to pay for their freedom, and what price Russia will pay for this senseless war against us," Zelenskiy said in a late-night address on Thursday.

"The catastrophic unfolding events could be still stopped if the world treated the situation in Ukraine as if it were facing the same situation, if the powers that be did not play around with Russia but really pressed to end the war."

Zelenskiy complained about disagreements within the EU on more sanctions against Russia and asked why some countries were being allowed to block the plan.

The EU is discussing a sixth round of punitive measures, including an embargo on Russian oil imports. It requires unanimity but Hungary opposes the idea on the grounds that its economy would suffer too much.