MOSCOW (AP) — Ukraine accused the Russian security services Saturday of planning and launching a massive cyberattack that locked up computers across the world.

The Ukrainian security agency, known as the SBU, alleged in a statement that similarities between the malicious software and previous attacks on Ukrainian infrastructure showed the participation of the Russian intelligence services.

The SBU added that the attackers appeared uninterested in making a profit from the ransomware program and were more focused on sowing chaos in Ukraine.

There was no immediate Russian response to the allegations. The Russian Foreign Ministry was closed for business Saturday.

Ukraine was the country hardest hit by the attack that started Tuesday, when computers at government agencies, energy companies and cash machines were temporarily disabled as their data was encrypted amid demands for ransom payments.

Russian companies, including the state-owned oil giant Rosneft, also said they were hit by the cyberattack.

Most of the organizations affected by the program recovered within 48 hours.

Ukraine has repeatedly accused Russia of sponsoring hacking attacks, including the hack of Ukraine's voting system ahead of 2014 national elections and an assault that knocked its power grid offline in 2015.

Relations between Russia and Ukraine collapsed when Moscow annexed Crimea in 2014 and began backing separatists fighting forces loyal to Kiev in eastern Ukraine.