U.S. President Donald Trump's demand on India to halt Russian oil imports could threaten billions in Russian revenues, prompt Moscow to retaliate by stopping a major U.S.-led oil pipeline and potentially lead to a new global supply crisis.

President Donald Trump says the United States and India are still negotiating on trade despite new tariffs slated to begin in a few days.

The president said Wednesday that imports from India would be subject to a 25 percent tariff as of Friday, as trade talks between the countries hit a stumbling block.