Investigators have found enough evidence to suspect Head of General Staff of the Russian Armed Forces Valery Gerasimov of direct involvement in worsening the conflict in eastern Ukraine.

"There is a lot of evidence. These are witnesses' testimonies, documents, military and legal documents, so-called reconnaissance reports, as well as other battle action and exit journals. All these documents are included in the materials of the case," Head of the Main Investigative Department of the Security Service of Ukraine (SBU) Hryhoriy Ostafiychuk said at a briefing in Kyiv on Wednesday.

He said that Ukrainian investigators also have proof, including "equipment left by Russian troops in our state, including near Ilovaisk."

"I think that according to the article 84 of the Criminal Procedural Code, this set of evidence is enough to reasonably issue a notice of suspicion and then send the case to the court," Ostafiychuk said.

In turn, Chief Military Prosecutor of Ukraine Anatoliy Matios said that back in July 2013, Gerasimov had initiated and received extended authority to coordinate the actions of all the federation executive agencies of Russia.

He said that investigation of other criminal proceedings uncovered acts of high treason by some SBU generals. In particular, Volodymyr Byk directly cooperated with representatives of Russian Armed Forces while he was head of Ukraine's counter-intelligence service.

In addition, in March-April 2014, illegal armed groups, including Vostok, Prizrak and Somali, were created with the funding of the Russian General Staff in Donetsk and Luhansk regions.

"They became a part of terrorist organizations – the so-called Donetsk and Luhansk People's Republics…," Matios said.

He went on to say that over 100 Russian military bases are now located in separatist held areas along with heavy military equipment and 30-40,000 troops.