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The special counsel Robert Mueller is homing in on two key events in which Michael Cohen, President Donald Trump's personal lawyer, was extensively involved, The Washington Post reported.

The first relates to the Trump Organization's push to secure a Trump Tower deal in Moscow in late 2015 and early 2016.

The second relates to a Russia-friendly "peace plan" for Russia and Ukraine that Cohen and two others were said to be instrumental in pushing for early last year.

Robert Mueller, the special counsel investigating Russia's interference in the 2016 US election, is digging into two episodes involving President Donald Trump's longtime personal lawyer, Michael Cohen, The Washington Post reported this week.

The first relates to the Trump Organization's effort in late 2015 to secure a Trump Tower deal in Moscow and Cohen's subsequent contact with a top Kremlin official at the height of the 2016 election.

The second relates to what The New York Times has described as a "peace plan for Ukraine and Russia" that Cohen was said to have been instrumental in developing and hand-delivering to Michael Flynn, the former national security adviser, before Flynn was forced to resign last year.

Stephen Ryan, Cohen's lawyer, denied that his client was under Mueller's scrutiny.

"Unsourced innuendo like this succeeds only because the leakers know the Special Counsel will not respond to set the record straight," he said in a statement to The Post.

Trump Tower Moscow

Cohen was in touch with a Russia-born businessman, Felix Sater, about the Trump Tower deal in October and November 2015, when Trump was a Republican presidential candidate.

Sater first sent a letter of intent to Cohen outlining the terms of the "Trump World Tower Moscow" deal on October 13, 2015, The Times reported. Andrey Rozov, a Russian investor, had already signed it by the time Sater forwarded it to Cohen for Trump's signature.

Sater attached a note addressed to Cohen that The Times' Maggie Haberman shared on Twitter last year.

"Lets make this happen and build a Trump Moscow," Sater wrote. "And possibly fix relations between the countries by showing everyone that commerce & business are much better and more practical than politics. That should be Putins message as well, and we will help him agree on that message. Help world peace and make a lot of money, I would say thats a great lifetime goal for us to go after."

Weeks later, the two men exchanged a series of emails gearing up to celebrate the Trump Tower Moscow deal. In the emails, obtained by The Times, Sater bragged about his relationship with Russian President Vladimir Putin and told Cohen he would "get all of Putins team to buy in" on the deal.

"Our boy can become president of the USA and we can engineer it," Sater wrote, according to The Times.

Sater added: "I will get Putin on this program and we will get Donald elected."

Sater told Talking Points Memo last August that his "last Moscow deal" for the Trump Organization "was in October of 2015" but that it "didn't go through because obviously he became president."

"Once the campaign was really going-going, it was obvious there were going to be no deals internationally," Sater said. "We were still working on it, doing something with it, November-December."

Cohen was advocating the project as late as January 2016, when he contacted Dmitry Peskov, a top aide to Putin, about pushing the Trump Tower Moscow deal through.

"Over the past few months I have been working with a company based in Russia regarding the development of a Trump Tower-Moscow project in Moscow City," Cohen wrote to Peskov, according to The Post, which cited a person familiar with the email. "Without getting into lengthy specifics, the communication between our two sides has stalled."

Cohen continued: "As this project is too important, I am hereby requesting your assistance. I respectfully request someone, preferably you, contact me so that I might discuss the specifics as well as arranging meetings with the appropriate individuals. I thank you in advance for your assistance and look forward to hearing from you soon."

Cohen told Vanity Fair last year that the proposal from Sater was "business as usual and nothing more," describing it as "just another project, another licensing deal." He added that he had "really wanted to see this building go up, because the economics were fantastic."

A Russia-friendly 'peace plan'

Donald Trump at a rally in Sparks, Nevada, on October 29, 2015. Reuters/James Glover II

Meanwhile, Mueller is also looking into whether Cohen had a role in delivering to Flynn a Russia-Ukraine "peace plan" that appeared to favor Moscow.

Flynn was forced to resign in February 2017 after it emerged that he misled Vice President Mike Pence about his conversations with Sergey Kislyak, Russia's ambassador to the US at the time.

The Times reported last year that Cohen, Sater, and the Ukrainian politician Andrey Artemenko were the key figures involved in pushing for the proposal. While Cohen and Sater are both longtime associates of Trump, Artemenko is said to have met with the Trump campaign before the election and has signaled opposition to Ukrainian President Petro Poroshenko.

Poroshenko, who assumed the presidency in 2014 after the ouster of Viktor Yanukovych, has demonstrated more affinity than his predecessor toward the West.

Yanukovych, a prominent figure in Ukraine's pro-Russia Party of Regions, fled the country amid widespread protests against his Russia-friendly positions and his decision to back out of a deal that would have promoted closer ties between Ukraine and the West while distancing the country from Russia. He was associated closely with Paul Manafort, the former Trump campaign chairman widely credited with helping Yanukovych win the election in 2010.

The plan Artemenko, Sater, and Cohen pushed would have the US lift sanctions on Russia in exchange for Moscow's withdrawing its support for pro-Russia separatists in eastern Ukraine. It would also allow Russia to maintain control over the territory of Crimea, which it annexed in 2014.

Cohen's account of his involvement in the conception and delivery of the plan evolved following The Times' report.

"Mr. Cohen told The Times in no uncertain terms that he delivered the Ukraine proposal to Michael Flynn's office at the White House," The Times' deputy managing editor said in a statement after the newspaper published the story. "Mr. Sater told the Times that Mr. Cohen had told him the same thing."

Cohen confirmed some details of the Times story to The Post, saying he met with Sater and Artemenko at a hotel in Manhattan in late January 2017 to discuss the plan. He added that the meeting lasted less than 15 minutes and that he left with the plan in hand.

He told Business Insider in February 2017 that he did not know what the plan was. Cohen then shifted his story again, saying he met with Artemenko for less than 10 minutes in New York to discuss a proposal Artemenko said "was acknowledged by Russian authorities that would create world peace."

"My response was, 'Who doesn't want world peace?'" Cohen said.

Later, Cohen told NBC News that even if he had delivered the peace plan to the White House, it wouldn't be a big deal.

"So what?" Cohen said. "What's wrong with that?"

Trump has repeatedly suggested that he would consider easing sanctions on Russia if it cooperated with the US on issues like counterterrorism. His administration has also adopted a softer stance toward Moscow than the previous one did.

Russia's economy was dealt a stinging blow in 2014 when President Barack Obama imposed sweeping sanctions to punish Russia for its aggression toward Ukraine and its annexation of Crimea.

The Obama administration announced another round of sanctions in December 2016 to penalize Russia for meddling in the presidential election. The US government also shuttered two Russian diplomatic facilities and expelled 35 Russian diplomats.

Last summer, Congress overwhelmingly voted to impose new sanctions on Russia. Trump signed them into law after facing public pressure from lawmakers and critics who accused him of catering to Putin's wishes.

But the White House has declined to enforce that law. The State Department has said its mere existence is enough to penalize Russia because it had already made a dent in Russian defense sales.

"From that perspective, if the law is working, sanctions on specific entities or individuals will not need to be imposed because the legislation is, in fact, serving as a deterrent," a State Department representative said.