KYIV (REUTERS) - Ukraine accused an unnamed group of Russian hackers on Wednesday (Feb 24) of trying to disseminate malicious documents through a web-based system on which government documents are circulated, but did not say whether any damage was caused.

Kyiv has previously accused Moscow of orchestrating large cyber attacks as part of a "hybrid war" against Ukraine, which Russia denies. The aim of the attack was to contaminate information resources on the System of Electronic Interaction of Executive Bodies, Ukraine's National Security and Defence Council said in a statement.

"The methods and means of carrying out this cyber attack allow (us) to connect it with one of the hacker spy groups from the Russian Federation," the council said, without identifying the group. It was the second cyber incident reported by the Ukrainian authorities this week.

On Monday, Kyiv accused unnamed Russian internet networks of attacks on Ukrainian security and defence websites.

Ukraine and Russia have been at loggerheads since Russia's annexation of Crimea from Ukraine in 2014 and involvement in a conflict in Ukraine's eastern Donbass region which Kyiv says has killed 14,000 people.