Schiff says GOP senators must agree to Bolton testifying

On Sunday, The New York Times, citing multiple people's descriptions of an unpublished draft manuscript by Bolton, reported Trump in August told his then-national security adviser that he wanted to continue holding military aid to Ukraine until the country helped with investigations into Democrats, including former Vice President Joe Biden.

Trump's purported statement, as described by Bolton, would directly tie the US military aid freeze with the President's requests that Ukraine announce investigations into his political rivals -- undermining a key pillar of the President's impeachment defense that the two circumstances are unrelated.

The news has placed new pressure on Senate Republicans to allow witnesses, including Bolton, to testify in the trial.

"I think for the senators, and I'm just not talking about the four that been so much the focus of attention, for every senator, Democrat and Republican, I don't know how you can explain that you wanted a search for the truth in this trial and say you don't want to hear from a witness who had a direct conversation about the central allegation in the articles of impeachment," Schiff told CNN's Alisyn Camerota on "New Day" Monday.

The President has denied Bolton's claims in a series of late night tweets, writing that he "NEVER told John Bolton that the aid to Ukraine was tied to investigations into Democrats, including the Bidens." There is no evidence of wrongdoing by Biden or his son Hunter.

Schiff, the chairman of the House Intelligence Committee, wouldn't say if the Democratic-led House would subpoena Bolton if the Senate doesn't.

"The reality is the senators ought to hear this witness firsthand," he told Camerota.

This story is breaking and will be updated.