US confirms its government networks have been hit by a major cyber-attack

The recent recurring cyber infiltration breach has affected most of the networks, the U.S. government has confirmed on Wednesday, as Reuters reported. Informed sources said earlier this week that hackers are believed to be working for Russia, and has spied on internal emails from the U.S. Treasury and Commerce Departments.

Concerns mount up as the hacks discovered so far are likely to be the tip of the iceberg, as cited by Reuters.

"This is a developing situation, and while we continue to work to understand the full extent of this campaign, we know this compromise has affected networks within the federal government," said a joint statement issued by the FBI, the Cybersecurity and Infrastructure Security Agency (CISA) and the Office of the Director of National Intelligence (ODNI). "Over the course of the past several days, the FBI, CISA, and ODNI have become aware of a significant and ongoing cybersecurity campaign. The FBI is investigating and gathering intelligence in order to attribute, pursue, and disrupt the responsible threat actors."

Two of the most sophisticated and disconcerting breaches were directed at the Pentagon and the Department of Homeland Security, which was considered to sabotage the American election system by CISA last month.

The White House national security adviser Robert O'Brien cut off a European visit on Tuesday and returned to Washington to deal with the attack.