In newly released testimony, two aides described concerns raised as they listened to U.S. President Donald Trump discussing political investigations with Ukraine's leader.

Tim Morrison, a former National Security Council official, voiced his concern after the call to the top NSC lawyers out of concern the call could leak. Morrison said he wanted to ensure the top attorneys, not their deputies saw the call.

He explained that his concern about the call leaking was because he "didn't necessarily fully understand how everybody would use it" but he worried it would wind up "politicizing Ukraine" and cost bipartisan support for the country.

"I was concerned about how the Ukrainians would internalize that," Morrison said.

House committees conducting the impeachment inquiry into Trump released transcripts on Saturday of closed-door depositions of Morrison and Williams.

Jennifer Williams, an aide to Vice President Mike Pence, told House investigators "the mention of those specific investigations" during the July 25 Trump-Zelensky call "seemed unusual as compared to other discussions with foreign leaders."

"I believed those references to be more political in nature and so that struck me as unusual," she said.

Prior to the July 25 call, Williams said she had not heard discussion in the Office of the Vice President or the White House of Crowdstrike or the DNC server, Ukrainian interference in the 2016 election, or investigating former Vice President Joe Biden and his son Hunter.

This story is breaking and will be updated.