The European Union's latest effort to restrict Russia's oil revenue is unlikely to hurt Moscow's war effort severely, leaving U.S. President Donald Trump's threat of secondary sanctions one of the few remaining economic levers to pressure the Kremlin.

The Kremlin is sticking to its war demands, even as President Trump makes new threats of sanctions that would go into effect if Russian President Vladimir Putin does not agree to a ceasefire with

The legislation, which would allow the president to levy a 500% tariff on imports from countries that purchase Russian uranium, gas and oil, has gained momentum in the Senate as Trump has signaled he will escalate US action against Russia.