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Ukrainian President Volodymyr Zelenskyy on Monday urged western nations to toughen sanctions quickly against Russia, including an oil embargo, to stop Moscow having escalating its measures against his country.
In his nightly video address to Ukrainians, a clearly irritated Mr Zelenskyy said the West had miscalculated last year in delaying sanctions and the invasion had followed.
"A full-scale war has begun," he said, occasionally banging his hands against a table.
"Now there are many hints and warnings that supposedly tougher sanctions, such as an embargo on Russian oil supplies to Europe, will be put in place if Russia uses chemical weapons.
"There are simply no words ... We, people who are alive, have to wait. Doesn't everything the Russia military has done to date warrant an oil embargo?
"Don't phosphorus bombs warrant it? A shelled chemical production facility or a shelled nuclear power plant doesn't warrant it?"
Russia's month-old invasion of Ukraine, the biggest European conflict since the Second World War, has seen over 3.8 million Ukrainians flee abroad, left thousands dead or injured and isolated Russia's economy.
Mr Zelenskyy said sanctions had to be "effective and serious" given Russia's actions to date.
"If the sanctions packages are weak or do not work strongly enough, if they can be circumvented, it creates a dangerous illusion for the Russian leadership, as if they will be permitted to continue doing what they are doing now," he said.
"Ukrainians are paying for this with their lives. Thousands of lives."
The United States has already introduced an embargo on Russian oil shipments.
But Europe, far more dependent on Russian energy, has been more hesitant.
