WASHINGTON, Feb. 15 (Xinhua) -- The U.S. government on Thursday accused the Russian military of launching the "most destructive and costly cyber-attack in history," but didn't provide any evidence.

The claim came hours after the British Foreign Office made a similar accusation, saying that the Russian government was behind the NotPetya cyber attack of June 2017.

The Kremlin responded by "categorically" rejecting Britain's accusations.

"We consider them to be unsubstantiated and groundless," Kremlin spokesman Dmitry Peskov was quoted as saying by Russian media.

According to a statement released by the U.S. Press Secretary, the attack spread worldwide and caused billions of dollars in damage across Europe, Asia and the Americas.

"It was part of the Kremlin's ongoing effort to destabilize Ukraine and demonstrates ever more clearly Russia's involvement in the ongoing conflict," it says.

The attack of a malware dubbed NotPetya disrupted numerous computer systems last June. It erupted first in Ukraine, but the virus later spread to many other countries, including Russia. The statement said that the "reckless and indiscriminate cyber-attack" will be met with international consequences.

In January, American intelligence officials referenced a classified report from the U.S. Central Intelligence Agency (CIA), alleging Russia's military spy agency GRU created NotPetya, according to a Washington Post story. But then the CIA declined to comment on it.

The only link known to the public till now was that the attack happened as Ukraine was about to celebrate its Constitution Day.

"This is nothing more than a continuation of the Russophobic campaign, based on no evidence," Peskov said.