Washington (CNN) An explosive allegation concerning John Bolton has given new ammunition to Democrats' demands for the Republican-controlled Senate to call the former national security adviser to testify at President Donald Trump's impeachment trial.

The New York Times reported that the book manuscript Bolton submitted to the White House for review alleges that Trump told Bolton that he wanted to continue to withhold military aid to Ukraine until Ukraine assisted with investigations into Democrats, including presidential candidate Joe Biden.

Trump denied the allegation in a tweet on Sunday night. On Monday morning, Trump made another claim.

"The Democrat controlled House never even asked John Bolton to testify. It is up to them, not up to the Senate!" he said on Twitter

Facts First: Trump's claim is false. House Democrats sent Bolton an official request to testify. He declined to appear -- because the White House did not authorize him to do so. Democrats did not seek to force him to testify, concerned about how long a legal battle over a subpoena would likely take, but they certainly did ask.