Yarosh announced the agreement on his Facebook page.
"I met with command of OUN – Nikolai Kokhanivsky and fellows. We agreed our positions on cooperation at foreign and domestic fronts. So, to the victory! Glory to Ukraine!" he wrote.
On May 14, Yarosh submitted to the Verkhovna Rada (the Ukrainian parliament) a bill on the Ukrainian volunteer corps. Earlier, he said there is mutual understanding between country’s security forces and the volunteer corps on cooperation.
The Right Sector was formed as a coalition of nationalist and neo-Nazi organizations during the Maidan protests in Kiev at the end of 2013.
In November 2014, Russia’s Supreme Court blacklisted Right Sector and the Ukrainian Insurgent Army (a separate militant wing of OUN) as an extremist organization and banned it in Russia. Earlier, Russia launched a criminal case against Yarosh for public incitement of terrorism.