Hackers have targeted Ukrainian state institutions about 6,500 times in the past two months, including incidents that showed Russian security services were waging a cyberwar against the country, President Petro Poroshenko said on Thursday.

In December, Ukraine suffered attacks on its finance and defense ministries and the State Treasury, which allocates cash to government institutions. A suspected hack also wiped out part of Kiev's power grid, causing a blackout in part of the capital.

"Acts of terrorism and sabotage on critical infrastructure facilities remain possible today," Poroshenko said during a meeting of the National Security and Defence Council, according to a statement released by Poroshenko's office.