WASHINGTON — President Obama imposed a new round of sanctions against Russia on Wednesday, targeting some of the crown jewels of the country’s financial, energy and defense industries in what officials described as the most punishing measures taken to date by the United States in retaliation for Moscow’s intervention in Ukraine.

The new actions will, among other things, restrict access to American capital markets for Russian giants like the Rosneft oil company and Gazprombank that operate worldwide. While the latest moves did not cut off entire sectors of the Russian economy, they went significantly further than the financial and travel limits imposed previously on several dozen individuals and their businesses.

The announcement reflected a decision by Mr. Obama to take more stringent steps than those taken by the United States’ European allies, which have far deeper economic ties to Russia. Meeting in Brussels, leaders of the European Union refused to match the American measures and instead adopted a more tempered plan that blocks new development loans to Russia and threatens to target more Russian individuals.

The disparate moves suggested a widening gulf in the response to the crisis in Ukraine and may dilute the impact of the American actions. But both sides emphasized their continued solidarity on the basic demands that Moscow halt the flow of fighters and weapons across the border with Ukraine, support a cease-fire and help facilitate the release of hostages held by pro-Russian separatists.