The Russian government may be sponsoring a hacking group that has targeted NATO, European states and countries in the Caucasus since 2007, a report has found.
The hackers being tracked as Advanced Persistent Threat 28 operate during times consistent with office hours in Moscow and St Petersburg and target information that can benefit the Russian government, said FireEye, a California-based network security company.
The group known as APT28, is a "skilled team of developers and operators collecting intelligence on defence and geopolitical issues - intelligence that would only be useful to a government", FireEye said.
"While we don't have pictures of a building, personas to reveal or a government agency to name," FireEye said, "what we do have is evidence of long-standing, focused operations that indicate a government sponsor - specifically, a government based in Moscow."
Russian president Vladimir Putin's spokesman, Dmitry Peskov, dismissed the report's findings, saying: "I don't know what FireEye is, so I can't trust in any report from this company."
The group's targets included the North Atlantic Treaty Organisation's special operations headquarters, the governments in Poland and Hungary and the ministries of defence and internal affairs in Georgia, which fought a war with Russia in 2008, FireEye said.