Ukrainian government websites have been hit by a series of malware attacks as tensions with Russia have increased.
TechWeekEurope reports that a number of sites in Ukraine have been hit by large Distributed Denial of Service (DDos) attacks, which involve making a site unavailable by overloading it with requests.
Although it is unclear who is responsible, TechWeekEurope says it has been handed data indicating that many of the attacking servers are location in Eastern Europe, especially in Russia.
The malware used to launch the attacks, known as DirtJumper, has previously been used in attacks on Ukrainian government sites in December, but only for a very short while. These latest attacks are much more sustained and also target news outlets.
Among the sites targeted were the Ukrainian state news agency Ukrinform and a small number of NATO websites. There were also suggestions that illegally installed equipment had been used to spy on members of the Ukrainian parliament.
Responsibility for the attacks on NATO sites was taken by a group calling themselves Cyber Berkut, who appear to hold sympathies with Russia.