President Petro Poroshenko has pardoned a Russian citizen arrested in eastern Ukraine and exchanged him for a Ukrainian serviceman held by Russian-backed separatists.

Poroshenko announced the exchange on his official website, which showed a photograph of him meeting early Tuesday with the freed Ukrainian, Andrei Grechanov.

The president said he pardoned Vladimir Starkov, a Russian who was arrested in July while driving a truck loaded with ammunition in eastern Ukraine and later sentenced to 14 years in prison. Ukrainian security services released a video in which Starkov acknowledged being a Russian military officer.

Russia has denied sending troops and weapons to eastern Ukraine, where separatists have been fighting government troops since April 2014 in a conflict that has killed more than 8,000 people.

A cease-fire has largely held since September.