Senate Minority Leader Chuck Schumer on Thursday dug in on his demand that the Senate impeachment trial of President Donald Trump include new documents and testimony after revelation of administration emails that show officials questioned the legality of delaying aid to Ukraine.

"The newly revealed unredacted emails are a devastating blow to Sen. McConnell's push to have a trial without the documents and witnesses we've requested," Schumer said in a statement, referring to Senate Majority Leader Mitch McConnell. "These emails further expose the serious concerns raised by Trump administration officials about the propriety and legality of the president's decision to cut off aid to Ukraine to benefit himself."

The website Just Security, which is based at the Center for Human Rights and Global Justice at the New York University School of Law, said a review of unredacted versions of Trump administration emails released as part of a lawsuit shows growing concern among Pentagon officials that a continued hold on the aid ordered by the president would violate the Impoundment Control Act. The law requires the executive branch to spend money as appropriated by Congress, and the documents show that the necessary steps to avoid running afoul of the act weren't being taken.