The Security Service of Ukraine (SBU) is checking reports on the possible involvement of Russian servicemen in the handover of weapons to Ukrainian MP Nadiia Savchenko and Head of the Officer Corps Prisoner Release Center Volodymyr Ruban, SBU Chief Vasyl Hrytsak has said.

"Investigators of the Security Service of Ukraine are currently checking data on the involvement of servicemen (Russian citizens) of the Russian Armed Forces in the transfer of weapons directly to Nadiia Savchenko and Volodymyr Ruban," he told reporters in Cherkasy region on Saturday, when asked about the data published earlier by Ukrainian Prosecutor General Yuriy Lutsenko.

Hrytsak expressed confidence that this case would be investigated "within a reasonable time" and that it would be transferred to court in a few months.

On May 11, Lutsenko said that Ukrainian investigators had identified Russian servicemen who supplied Savchenko with weapons to commit a terrorist attack: "Colonels of the Russian Armed Forces are behind the military units from which the weapons were transferred to carry out the terrorist attack. They will appear in criminal proceedings."

Ruban was detained at a Donbas checkpoint on March 8 while trying to smuggle an arsenal of weapons into the part of Ukraine not controlled by Kyiv.

Ruban is suspected of preparing armed attacks on top state officials, preparing a terrorist act with the use of weapons and explosions that could pose a threat to life and health of people.

According to investigators, Ruban planned "to use mortars, grenade launchers, small arms and explosive devices to carry out an armed attack on the residences of statesmen, political leaders, in particular: Petro Poroshenko, Arsen Avakov, Arseniy Yatsenyuk, Oleksandr Turchynov and others with the purpose of their murder."

On March 9, the Shevchenkivsky District Court of Kyiv arrested Ruban for two months, until May 6. On March 20, Kyiv Court of Appeal upheld this decision.