Vladimir Putin has blamed the US for the global cyber attack that has crippled computer systems around the world since Friday.
The cyber attack, which wreaked havoc at dozens of NHS trusts on Friday, has continued to spread, hitting thousands of computers in China and Japan.
Putin said Russia had "nothing to do" with the attack and blamed the US for creating the hacking software that affects Microsoft computers.
"Malware created by intelligence agencies can backfire on its creators," said Putin, speaking to media in Beijing. He added that global leaders needed to discuss cyber security at a "serious political level" and said the US has backed away from signing a cyber security agreement with Russia.
Authorities fear a second wave of the "WannaCry" ransomware could hit systems as people return to work and switch on their computers on Monday morning.
Japanese computer experts said around 2,000 PCs had been affected while the Chinese news agency Xinhua reported that almost 30,000 had been hit.
Authorities had warned of a day of chaos ahead of Monday, with the National Cyber Security Centre saying that existing infections could spread through computer systems.