"A Ukrainian politician who was in contact with Trump's associates about the controversial plan for the settlement of the conflict between Ukraine and the Kremlin-backed separatists said that he was summoned to testify before a grand jury in connection with the investigation of special prosecutor Robert Mueller," writes Politico.

Andrei Artemenko told the publication that the meeting is scheduled for Friday. He suggested that he would be asked about the peace plan, of which he spoke with Trump's personal attorney Michael Cohen. "I received a summons last week," he told Politico and added that he intends to submit and appear personally.

"In February 2017 The New York Times wrote that Artemenko contacted the former Trump business partner Felix Suter to find out how he could bring his plan for peace in Ukraine to the Trump administration. Suter introduced Artemenko to Cohen, who left the plan in the office of Michael Flynn, then the national security adviser, NYT reported. Cohen denied this, saying that he threw out the document, "the publication recalls.

The news caused a scandal in Ukraine. Among the proposals was the idea to rent Crimea to Russia for 50 years in exchange for ending the war in Donbass. Unofficial efforts were also aimed at removing from Russia the sanctions imposed by the White House under the leadership of Obama.

"Artemenko's testimony can help Mueller's team repair the gaps with the peace plan that Muller was investigating in part because of the role of Cohen and Sutter in it - they also together tried to launch a Trump brand building in Moscow in early 2015," reads the article. The plan may be of interest to Mueller also because he appeared shortly after Flynn on the phone discussed the lifting of sanctions with the Russian ambassador.

Cohen told The Washington Post that at the meeting Artemenko boasted that the Russian authorities agree with the proposal. Artemenko said that he did not speak with any Russian official and that the proposal arose during consultations with Ukrainian officials.