A file picture taken on October 15, 2014 shows servicemen of Ukrainian border standing guard at the Goptivka border crossing on the Urkainian-Russian border, north of Kharkiv, eastern Ukraine. (AFP Photo)

KIEV, March 2 (Xinhua) -- Kiev released two Russian citizens in exchange for two Ukrainian border guards, Ukraine's interior minister said on Friday.

Under the prisoner swap, the Ukrainian border officers, Bogdan Martson and Igor Dziubak, who were detained by Russian forces in October last year, were returned to Ukraine, Interior Minister Arsen Avakov wrote on Facebook.

The minister gave no details on the identity of the released Russian citizens.

Meanwhile, the Interfax-Ukraine news agency said that Kiev handed over to Moscow two Russian border guards, Vladimir Kuznetsov and Askar Kulub, who were detained in Ukraine's southern Kherson region in the summer of 2017.

According to the news agency, the prisoner swap took place on neutral territory of the Ukrainian-Russian border near the Goptovka checkpoint in Ukraine's eastern Kharkiv region.

The Russian authorities have not commented on the prisoner exchange.

Relations between Kiev and Moscow have soured since 2014 when Crimea joined Russia following a referendum, but Ukraine said the peninsula was illegally annexed.