The Organization for Security and Cooperation in Europe (OSCE) has suffered a "major" cyberattack, a spokeswoman has confirmed.
Ursula Froese told RFE/RL on December 28 that the attack, first reported by the French daily Le Monde, took place in early November.
She said in an e-mail that the Vienna-based organization "became aware of a major information security incident" that compromised "the confidentiality "of its IT network.
She said the attack did not disrupt the organization's operations.
"The OSCE was able to operate, since its computer network services were not disrupted by the attack," the spokeswoman said.
According to Le Monde, a Western intelligence agency believes that the Russian hacker group APT28 was behind the attack.
The same source told Le Monde that the group was also behind attacks on the U.S. Democratic Party leadership during the U.S. presidential campaign.
The OSCE spokeswoman said her organization could not confirm the claim.
"As with all these cases, it is not possible to determine with certainty the identity of the attackers," Froese said.
With reporting by AFP and Reuters