The criminal investigation into possible Yovanovitch spying is in response to the publication of US House Intelligence Committee notes, suggesting that she was illegally spied on in Ukraine, the ministry said.
The US State Department has not answered several CNN questions about Yovanovitch's possible surveillance and will open its own investigation.
However, House Foreign Committee chairman Rep. Eliot Engel wrote in a letter on Wednesday that his team received a personal pledge from Assistant Secretary of State Diplomatic Security Michael Evanoff that the department would open an investigation. immediate about it.
A spokesman for the House Foreign Relations Committee confirmed to CNN on Thursday that the State Department told staff it would open an investigation.
"Ukraine's position is not to interfere in US internal affairs. However, the published records contain the fact that a possible violation of Ukrainian law and the Vienna Convention on Diplomatic Relations, which protects the rights of a diplomat in another country's territory, "said a statement from the ministry.
"Ukraine cannot ignore these illegal activities on its territory. After reviewing these materials, the Ukrainian National Police, after their publication, initiated criminal proceedings," the statement said.
"Needless to say, the notion that US citizens and others were monitoring Ambassador Yovanovitch's movements for unknown purposes is disturbing," Lawrence S. Robbins, Yovanovitch's lawyer, said in a statement. "We trust the appropriate authorities will conduct an investigation to determine what happened."
This story has been updated with additional information.
CNN's Zachary Cohen and Kylie Atwood contributed to this report.