Ukrainian President Volodymyr Zelenskky has urged Western nations to toughen sanctions quickly against Russia. In his nightly video address to Ukrainians, he said the measures should include an oil embargo. Zelenskky said the West had miscalculated last year in delaying sanctions, and the Russian military operation had followed. He said sanctions had to be "effective and serious" given Russia's actions to date. The United States has already introduced an embargo on Russian oil shipments.