The Ukrainian government has opened an investigation into the possible illegal surveillance of Marie Yovanovitch when she was the US ambassador to Kyiv, following the publication of messages about her between two associates of Donald Trump’s personal lawyer.

The Ukrainian interior ministry issued a statement on Thursday saying that its position was not to interfere in US domestic affairs, but that press reports of messages contain “a possible violation of the law of Ukraine and the Vienna convention on diplomatic relations, which protects the rights of a diplomat on the territory of the foreign country”.

The statement said Ukrainian authorities had initiated criminal proceedings and asked the US for cooperation.

“In accordance with the international legal mechanisms, the minister of internal affairs of Ukraine, Arsen Avakov, suggested that the US side to take part in the investigation,” the statement said.

Neither the US state department nor the justice department responded to a request for comment.

The state department has yet to make any statement on the possibility that Yovanovitch had been put under surveillance, after WhatsApp messages were released on Tuesday by the House intelligence committee between Trump donor Robert Hyde and Lev Parnas, a Soviet-born Florida businessmen.

Both men had ties to Rudy Giuliani, Trump’s attorney and adviser, who the president had assigned to take the lead in persuading the Ukrainian government to open an investigation into his political rival former vice-president Joe Biden and his son Hunter.

In an interview on Wednesday night, Parnas, a 47 year-old Republican donor who has been charged for campaign finance violations, told MSNBC that Trump “knew exactly what was going on” in the pressure campaign on Kyiv.

Yovanovitch was viewed as an obstacle by Giuliani because she did not allow the embassy to become involved in the trawl for damaging material on the Bidens. She was also viewed as an enemy by former Ukrainian prosecutor Yuriy Lutsenko, who had offered to help find compromising information in return for favours from Washington.

During the campaign, Parnas received messages from Hyde appearing to describe surveillance of Yovanovitch, who referred to as “a bitch”.

Hyde allegedly texted to Parnas: “She’s talked to three people. Her phone is off. Her computer is off.”

Hyde said Yovanovitch was under heavy security and that “we have a person inside”.

In his MSNBC interview, Parnas said Hyde was “drunk all of the time” and a “weird character”.

“He was either drunk or making himself bigger [more important] than he was. I didn’t take him seriously,” Parnas said.

Hyde distanced himself from Parnas, calling him a “dweeb” and said he was only “joking around” after a few drinks by sending “colourful texts”. The texts, however, were sent over the course of an entire week.

The Washington Post reported on Thursday that Hyde had been involuntarily committed to a psychiatric hospital last May, following an incident at Trump’s Doral resort outside Miami.

Hyde is reported to have told the police that he had been “set up and that a hit man was out to get him” and he also “spoke about emails he sent that may have placed his life in jeopardy”. According to the report, he believed that painters and landscape workers were trying to harm him and that the Secret Service was watching him.

Yovanovitch’s lawyer, Lawrence Robbins, issued a statement after the publication of the texts, and called for an inquiry.

“Needless to say, the notion that American citizens and others were monitoring Ambassador Yovanovitch’s movements for unknown purposes is disturbing,” Robbins said. “We trust that the appropriate authorities will conduct an investigation to determine what happened.”

Robbins did not immediately reply to a query on whether Ukrainian authorities had been in touch about their investigation.

In a separate request, Ukraine appealed to the FBI for help in another investigation of a suspected cyber-attack by Russian military hackers on Burisma Holdings, a Ukrainian energy company, which hired Hunter Biden as a board member.

The pressure by the Trump camp on the Ukrainian government was aimed in part at looking for damaging information about the younger Biden’s role as a Burisma board member.