KIEV, Dec. 29 – Russian security services have waged a cyberwar against Ukraine by launching 6,500 attacks on critical infrastructure and government agencies over the past two months, President Petro Poroshenko said on Thursday.

The allegations come as U.S. President Barack Obama announced new sanctions against Russia for its alleged role in cyber interference with U.S. presidential election earlier this year.

The Ukrainian attacks were designed to inflict serious damage on critical infrastructure, such as disrupting disbursement of money by the State Treasury in December as well as shutting down power supplies in parts of the capital of Kiev.

“The cyber attack on the State Treasury on December 6 was an emergency event that had disrupted the system that handles 150,000 budget transactions per day,” Poroshenko said during a meeting of the National Security and Defense Council.

Similar attacks earlier this year were aimed at the state railroad company UkrZaliznytsia, the international airport Boryspil and some attacks even targeted nuclear power plants.

"Acts of terrorism and sabotage on critical infrastructure facilities remain possible today," Poroshenko said.

Russia’s attacks on Ukraine underscore the capability of its robust cyber force and show potential ways that the conflict may escalate on a larger scale between Russia and the U.S.

"We are dealing with global security challenges that Russia throws on the entire Euro-Atlantic community," Poroshenko said.

Relations between Kiev and Moscow collapsed in 2014 following Russia's annexation of Crimea and support for pro-Russian separatists in eastern Ukraine, where fighting continues despite a ceasefire agreement.

The attack on the State Treasury halted its systems for several days, meaning state workers and pensioners had been unable to receive their salaries or payments on time.

Cyber security firm CrowdStrike said last week a hacking group linked to the Russian government likely used a malware implant on Android devices to track and target Ukrainian artillery units from late 2014 through 2016.

Its findings are the latest to support a growing view among Western security officials and cyber security researchers that Russian President Vladimir Putin has increasingly relied on hacking to exert influence and attack geopolitical foes.

Russia has repeatedly denied hacking accusations.

Poroshenko's comments come as the Obama administration announced retaliatory measures against Russia for hacking into U.S. political institutions and individuals and leaking information in an effort to help Donald Trump win the presidency. Trump has dismissed the assessments of the U.S. intelligence community.

In December 2015, Ukrainian regional power company Prykarpattyaoblenergo reported an outage, saying the area affected included the regional capital Ivano-Frankivsk. Ukraine's state security service blamed Russia.

Experts widely described that incident as the first known power outage caused by a cyber attack. The U.S. cyber firm iSight Partners identified the perpetrator as a Russian hacking group known as "Sandworm".

As a result of the cyber attacks, Ukraine's security council agreed measures to protect state institutions, the statement said. It did not disclose what the measures were. (nr/rt/ez)