Ukrainian President Volodymyr Zelensky has complained about divisions inside the European Union over more sanctions against Russia and asked why some nations were being allowed to block the plan.
The EU is discussing a sixth round of punitive measures, including an embargo on Russian oil imports. Such a move requires unanimity but Hungary opposes the idea for now on the grounds its economy would suffer too much.
"How many more weeks will the European Union try to agree on a sixth package?" Mr Zelensky said in a late-night address, noting that Russia was receiving a billion euros a day from the 27-nation bloc for energy supplies.
He said: "Of course I am grateful to those friends who are advocating new sanctions. But where do the people blocking this sixth package get their power from? Why are they allowed to hold such power?"
Germany hopes talks on the new round of sanctions will be completed soon but it will not be a topic at a leaders' summit next week, a German official said.
Mr Zelensky's comments mark the second day in a row that he has sharpened his criticism of the world's approach to the war.
He said: "Pressure on Russia is literally a matter of saving lives. And every day of procrastination, weakness, various disputes or proposals to 'pacify' the aggressor at the expense of the victim merely means more Ukrainians being killed".
Mr Zelensky also accused Russia of carrying out "an obvious policy of genocide" in his country's eastern Donbas region.
He said Moscow's offensive in Donbas could end up leaving the region "uninhabited", accusing the Russians of wanting to reduce its cities to ashes.
"All this, including the deportation of our people and the mass killings of civilians, is an obvious policy of genocide pursued by Russia."
Russian President Vladimir Putin in late February sent troops into Ukraine, saying the campaign aimed to stop the "genocide" of Russian speakers in the pro-Western country.
In April, Ukraine's parliament backed a resolution recognising the actions of the Russian military in the country as "genocide".
US President Joe Biden used the same expression, saying Mr Putin appeared intent on "trying to wipe out the idea of even being able to be a Ukrainian".
Canadian Prime Minister Justin Trudeau echoed the claim.
On Wednesday he savaged suggestions that Kyiv make concessions to bring peace, saying the idea smacked of attempts to appease Nazi Germany in 1938.
He also reiterated complaints that the world had so far failed to totally isolate the Russian banking system and was not providing heavy weapons quickly enough.
Russia calls its actions in Ukraine a "special operation "that it says is not designed to occupy territory but to destroy its southern neighbour's military capabilities and capture what it regards as dangerous nationalists.