In his latest video address, Ukraine's president says Moscow is making so much money from oil exports that it doesn't need to take peace talks seriously.
Ukraine's President Volodymyr Zelenskyy has said he is grateful for Western sanctions but argues they don't go far enough.
In his latest video address released early on Thursday, he called on Western politicians to agree quickly on an embargo of Russian oil, complaining that their failure to do so was costing Ukrainians their lives.
Zelenskyy said Moscow was making so much money from oil exports that it did not need to take peace talks seriously and called on the "democratic world" to shun Russian crude.
He said some politicians were "unable to decide how to limit the flow of petrodollars and oil euros to Russia so as not to put their own economies at risk".
"The only question is how many more Ukrainian men, how many more Ukrainian women, the Russian military will have time to kill in order for you, certain politicians - and we know who you are - to find some determination," he said.
The president also said he would continue to insist Russian banks be completely blocked from the international finance system.
The US and the UK announced new sanctions against Russia on Wednesday. Washington's measures include a move to ban Russian oil imports. The new British moves include a pledge to end dependency on Russian coal and oil by the end of 2022.
EU member states are still trying to overcome their differences as they look to approve a fifth round of sanctions. The Commission has proposed a ban on coal imports and the closure of European ports to Russian ships.
"Measures on oil and even gas will also be needed sooner or later," European Council President Charles Michel said on Wednesday.
Hungary, which has a close relationship with Vladimir Putin, is now the most reluctant country to impose sanctions on oil and gas.
On Wednesday, EU Council President Charles Michel said moves against Russian oil and gas were likely to be needed eventually.
The bloc's foreign policy chief Josep Borrell said the EU had spent 35 times more on buying Russian energy than it had on weapons for Ukraine since the start of the war.
Ukrainian lawmaker Oleksiy Goncharenko called for an immediate end to business with Russia after he visited Bucha.
“In every barrel of oil, there is Ukrainian blood,” he told Euronews. The member of Ukraine's parliament added that he saw 50 bodies in the city, including one child.
“I am afraid about what is happening in Mariupol is even worse,” he added. “Because there the count of victims will be in the thousands, which is absolutely awful.”
Zelenskyy also accused Russia of trying to hide the evidence of war crimes to interfere with the international investigation.
“We have information that the Russian troops have changed tactics and are trying to remove the dead people, the dead Ukrainians, from the streets and cellars of territory they occupied. This is only an attempt to hide the evidence and nothing more,” he said on Wednesday.
He added that thousands of people were now missing, either dead or deported to Russia.