Russia has freed jailed Ukrainian servicewoman Nadiya Savchenko, who became a symbol of resistance against Moscow.
Savchenko arrived back in Kiev on Wednesday as part of a prisoner swap with two alleged Russian soldiers.
She was sentenced to 22 years in jail for killing two Russian journalists in eastern Ukraine, charges she denied.
The two Russians — Yevgeny Yerofeyev and Alexander Alexandrov — are being flown from Kiev to Moscow.
Savchenko was captured in 2014, as pro-Russian separatists in eastern Ukraine battled government forces.
She was charged with directing artillery fire that killed the two journalists, but she says she was kidnapped prior to the attack and handed over to the Russian authorities.
Her time in jail saw her mount a hunger strike and she was even elected in absentia to Ukraine's parliament.
'Jaws of Mordor'
The two men are said to be on board a plane belonging to Russian President Vladimir Putin.
Ukraine said the pair were elite members of Russian military intelligence but Russia insisted they were not on active duty when they were captured in eastern Ukraine.
They were sentenced to 14 years in jail last month after being found guilty of waging an "aggressive war" against Ukraine, committing a terrorist act and using weapons to provoke an armed conflict.
Ukraine and the West have repeatedly called for Savchenko's release and a prisoner swap has long been considered likely.
"It's been a long and complicated road," one of her lawyers, Nikolai Polozov, told AFP.
"But we have been able to prove that there are no insurmountable tasks and we've managed to free the hostage from the jaws of Mordor," he added, referring to the land controlled by the main antagonist in the Lord of the Rings saga.