Russia warned the West on Thursday that cyber attacks against its infrastructure risked leading to direct military confrontation, and that attempts to challenge Moscow in the cyber sphere would be met with targeted countermeasures.
The warning comes after Russia's housing ministry website appeared to be hacked over the weekend, with an internet search for the site leading to a "Glory to Ukraine" sign in Ukrainian.
In a statement, the foreign ministry said that Russia's critical infrastructure and state institutions were being hit by cyberattacks and pointed to figures in the United States and Ukraine as being responsible.
"Rest assured, Russia will not leave aggressive actions unanswered," it said. "All our steps will be measured, targeted, in accordance with our legislation and international law."
The statement, issued by the ministry's head of international information security, said Washington was "deliberately lowering the threshold for the combat use" of IT.
"The militarization of the information space by the West, and attempts to turn it into an arena of interstate confrontation, have greatly increased the threat of a direct military clash with unpredictable consequences," it said.
The websites of many state-owned companies and news organisations have suffered sporadic hacking attempts since Russia invaded Ukraine on Feb. 24, often to show information that is at odds with Moscow's official line on the conflict.
Moscow says it is carrying out a "special military operation" in the neighbouring country to disarm it and protect it from fascists. Ukraine and Western countries dismiss Russia's claims as a pretext for an illegal invasion.
President Vladimir Putin said in May that the number of cyberattacks on Russia by foreign "state structures" had increased several times over and called on the country to bolster its IT security.
(Reporting by Reuters; Editing by Mark Trevelyan and Jonathan Oatis)