Donald Trump's campaign chair and convention manager Paul Manafort appears at a press conference at the Republican Convention in Cleveland Thomson Reuters

The chairman of Donald Trump’s campaign was involved in encouraging Crimean independence from Ukraine, the Times of London reported Wednesday, citing a leaked memo.

The Times of London reported on a memo that was said to reveal Paul Manafort's involvement in the campaign to win support for the eventual annexation of the Crimean peninsula, which happened in 2014. According to the UK newspaper, a Ukrainian prosecutor is investigating Manafort for "conspiring with a criminal organization" and "inciting ethnic hatred and separatism."

In the international community, the annexation of Crimea is widely considered to be an illegal move by Russia.

In 2006, Manafort was behind demonstrations in Crimea against NATO, the Times reported. Viktor Yanukovych's pro-Russian Party of Regions led the protests. Russia is known to stand against NATO, an alliance it is not a member of.

The memo from the prosecutor said: "It was his political effort to raise the prestige of Yanukovych and his party — the confrontation and division of society on ethnic and linguistic grounds is his trick from the time of the elections in Angola and the Philippines. While I was in the Crimea I constantly saw evidence suggesting that Paul Manafort considered autonomy [from Ukraine] as a tool to enhance the reputation of Yanukovych and win over the local electorate."

In the past, Republicans have supported arming Ukrainians to fight Russian forces trying to move in on parts of the country. But since Trump became the Republican nominee for president, language in the party platform that referenced supporting Ukrainian nationalists was removed.

People within the party blamed Manafort, who worked as a consultant for Yanukovych's government.

Manafort has also been accused of accepting payments from the Yanukovych regime without disclosing them to the US government, which would be illegal.

The Trump campaign had not commented on the Times' report by Wednesday afternoon.

For the past two months, Manafort has effectively been running Trump's campaign. But on Wednesday the campaign announced that it hired Breitbart News chairman Steve Bannon to be Trump's campaign manager in a move that is thought to be designed to lessen Manafort's power.

Trump himself seems to have been influenced by Manafort's loyalties. He suggested in an interview last month that he supported Russia's invasion of Crimea.

"You know, the people of Crimea, from what I've heard, would rather be with Russia than where they were," he said in an interview.

The campaign of Hillary Clinton, the Democratic nominee for president, slammed the Trump campaign's perceived cozying up to Russia in a conference call Wednesday.

"We've obviously seen that Trump's own views and the Republican platform itself has notably backed Russian views and Russian policies, so it paints a very disturbing picture and I think the voters need to pay a lot of attention to that," Robby Mook, Clinton's campaign manager, said.

Ukraine is still a war zone, with Russian-backed separatists fighting Ukrainian nationalists for control.