Ukraine said Sunday that Russia was responsible for a hack that vandalized its official websites, alleging that Russia is increasingly engaging in a "hybrid war" with its neighbor.

According to The Guardian, Ukraine's ministry of digital transformation blamed Russia for the breach, which was intended to "destabilize" an already sensitive environment and weaken trust in the Ukrainian government.

While officials did not elaborate on the evidence attributing the hack to Russia, Microsoft provided facts late Saturday indicating the attack was carried out by a hostile nation.

The Associated Press reports that the attack's still-unidentified hackers also posted a message telling Ukrainians to "be afraid and prepare for the worse."

"All evidence points to Russia as the perpetrator of the cyberattack. Moscow "continues to fight a hybrid war and is aggressively expanding its troops in the information and cyberspaces," the ministry statement.

According to Microsoft's Threat Intelligence Center, the code was pure destructive malware masquerading as ransomware. It included a ransom note, a crypto wallet, and an encrypted message identifier, but no way for recovering the data.

A representative for Russian President Vladimir Putin refuted the charges in an interview with CNN, accusing Ukrainians of "blaming everything on Russia," including "poor weather" in their nation.

Russia has attacked Ukraine via cyberspace in 2014, 2015, and 2017. Around the time of the incident, negotiations between the U.S. and Russia broke down after Russian officials refused to withdraw soldiers from the Ukrainian border.

The strike comes as a Russian invasion of Ukraine looms and diplomatic efforts to end the tense situation appear to have stagnated.

Microsoft stated in a brief blog post Saturday that the malware was discovered on Thursday. That would correspond to the attack that took down approximately 70 Ukrainian government websites concurrently.

The company stated that it was unsure how many further organizations in Ukraine or elsewhere would be affected, but anticipated learning of additional intrusions.

Jake Sullivan, the U.S. national security advisor, said the U.S. and private-sector entities were still investigating the origins of the attacks. He stated that the U.S. has been warning about the danger of Russian cyberattacks for months and has been assisting Ukraine in strengthening its defenses.

Ukraine and its allies have been concerned for months about indicators of an impending Russian invasion, and the U.S. reported on January 14 that Russia was preparing a false flag operation to justify an assault.

The cyberattack looks to be escalating those tensions and may have crippled Ukraine's government infrastructure at an inopportune time.