The main negotiator for Russia's $3 billion loan to Ukraine in December 2013 was the son of disgraced ex-Ukrainian President Viktor Yanukovych, Oleksandr, former Russian Duma deputy Ilya Ponomarev has said.

"As far as I know, the principle negotiator from the Ukrainian side was Oleksandr Yanukovych, the president's son. This information was known to several members of Ukraine's Presidential Administration at the time. They personally were engaged in the loan talks," Ponomarev said on Wednesday during the state treason trial against Yanukovych in Kyiv's Obolonsky District Court in Kyiv.

According to Ponomarev, Russia's First Deputy Prime Minister Igor Shuvalov and his team were tasked to support Yanukovych and his cronies by finding a way to get them to agree not to sign the EU-Ukraine Association agreement and remain in Russia's sphere of influence.

"In September 2013, a 'non-standard' scheme to render financial assistance to Ukraine was worked out connected to a bond issue. Russia pledged to buy a certain amount of Ukrainian government bonds. The first tranche was for $3 billion. The total amount was envisaged at $15 billion," Ponomarev said.

"It was a classic insider deal. Its essence was not to transfer money directly, but to enrich certain individuals, in this case to the son of Yanukovych, using the bond markets. At least one large investment fund, Franklin Templeton, took part. There were also a number of similar trades made, when these bonds were sold at a discount and their value later increased," he said.

Ponomarev confirmed what he said to prosecutors during pretrial interviews. He said Viktor Yanukovych received $1 billion in the deal.

"I confirm this. He was paid off directly," he said.