Pechersky District Court of Kyiv has extended the pre-trial investigation and the custody of Russian Yevgeny Yerofeyev until October 17, Yerofeyev's lawyer Oksana Sokolovska told Interfax-Ukraine.

"We have had the court ruling on the extension," she said on Monday.

Sokolovska reported earlier that the term of custody had been extended until October 17 for another Russian, Alexander Alexandrov. The pre-trial investigation was extended until the same day.

Ukraine's Deputy Prosecutor General, Chief Military Prosecutor Anatoliy Matios confirmed the information.

Yerofeyev and Alexandrov were detained by Ukrainian servicemen on May 16, 2015, in the anti-terrorist operation zone, near the town of Schastia (the Luhansk Region). One of them was wounded in the arm and the other in the leg.

Ukraine described Yerofeyev and Alexandrov as Russian soldiers. In response to that the Russian defense ministry informed that Yerofeyev and Alexandrov were Russian citizens but not actual military servicemen of the Russian armed forces at the point of their detention.

A court in Kyiv ruled on the arrest of the two Russians.

On July 28, Yuriy Tandyt, an advisor to the head of the Ukrainian Security Service (SBU), revealed that the Alexandrov's and Yerofeyev's trial will start in September and must be held in Ukraine.