Ukrainians Hennadiy Afanasyev and Yuriy Soloshenko, who were convicted in Russia, are already on board the plane, which is headed for home, Ukraine's President Petro Poroshenko has said.

"At last! Yuriy Soloshenko and Hennadiy Afanasyev are already on board the Ukrainian aircraft and are flying from Moscow to Ukraine. How long did we fight for this moment!" Poroshenko said in a statement posted on his Facebook at around 15:00 Kyiv time on Tuesday.