Mr Parnas alleged Mr Trump ordered the vice president to stay away at the behest of Mr Giuliani to send a clear message to the incoming Ukrainian administration that they needed to take seriously the demand for an investigation into Joe Biden, a Democratic presidential candidate seen as a potential threat to Trump's 2020 reelection.
Parnas, the indicted associate of Rudy Giuliani, said on one occasion, he told Trump that Yovanovitch was "badmouthing him, and saying he was going to get impeached".
Trump has strongly denied allegations he ordered a campaign pressuring Ukrainian officials to investigate the business dealings of former vice president Biden and his son, part of the impeachment inquiry that will formally read out charges facing the president in the Senate Thursday.
The allegations about surveillance attempt emerged on Tuesday when House Democrats released text messages and documents suggesting Lev Parnas, an associate of Giuliani, talked about tracking Yovanovitch past year.
On Tuesday, documents recently released by congressional Democrats indicated that Marie Yovanovitch, a former U.S. ambassador to Ukraine, was subjected to surveillance and possibly facing a threat while working in Kiev, with Mike Pompeo finally commenting on the matter.
Harvey and Parnas also discussed John Solomon, the former Hill columnist, who wrote articles criticizing former U.S. ambassador to Ukraine Marie Yovanovitch.
The Government Accounting Office issued its report finding that President Trump and his staff did in fact break federal law when they withheld $214 million in aid Congress had authorized for Ukraine in its conflict with Russian-sponsored separatist forces.
Trump impeachment - what happens next?
Collins is pushing to have at least the promise of witness votes included in the organizing resolution. Bolton's remarks, recalled by witnesses in the House Investigation, could cut off several testimonies.
The new documents also show communications between Parnas and Nunes aide Derek Harvey, in which they arrange interviews with Ukrainian officials and apparent meetings at the Trump International Hotel in Washington, D.C., including with Giuliani.
"This is the general prosecutor that got fired by Biden", Parnas wrote to Harvey in March after sending a link to a web page titled "Viktor Shokin", a former Ukrainian prosecutor. "Let me know", Parnas texted Harvey on April 19, 2019. The Belgium number, whose identity is not known, writes "My contacts are checking", adding, "I will give you the address next week".
But newly released text messages by House Democrats tell a different story. "So that's where I think the smear campaign started coming about".
Hunter Biden, the son of Trump's opponent and former United States vice president, Joe Biden, was on the board of that company.
"Can you come now", asks Parnas.
"We do our best to make sure that no harm will come to anyone, whether that was what was going on in our embassy in Baghdad last week or the work that was going on in Kyiv up and through the spring of a year ago when Ambassador Yovanovitch was there, and in our embassy in Kyiv even today", he said.
Trump and his supporters also repeatedly vilified Yovanovitch, who was abruptly recalled from her post roughly two months after Hyde discussed her movements with Parnas.