Beijing on Tuesday dismissed allegations that a state-sponsored Chinese actor was responsible for a cyber breach at the US Treasury Department, labeling the claims as "groundless".

In a letter to Congress obtained by AFP, the Treasury disclosed that the attack had granted access to some of its workstations.

According to the department, the breach occurred earlier this month when a third-party cybersecurity service provider was compromised, enabling the attacker to remotely access certain workstations and unclassified documents.

China denied the allegations, with the Foreign Ministry asserting that Beijing "has always opposed all forms of hacker attacks, and we are even more opposed to the spread of false information against China for political purposes."

"We have stated our position many times regarding such groundless accusations that lack evidence," said Foreign Ministry spokesperson Mao Ning.

The Treasury, alerted to the incident by its provider BeyondTrust, contacted the US Cybersecurity and Infrastructure Security Agency and has been cooperating with law enforcement to assess the impact.

"The compromised BeyondTrust service has been taken offline and there is no evidence indicating the threat actor has continued access to Treasury systems or information," the department's spokesperson stated.

In a letter addressed to the leadership of the Senate Banking Committee, the Treasury attributed the breach to "a China state-sponsored Advanced Persistent Threat (APT) actor."

An APT refers to a sophisticated cyberattack where an intruder gains and maintains unauthorized access to a target, often remaining undetected for an extended period.

The Treasury did not specify which systems or data were affected but indicated that additional details would be included in a supplemental report to be released later.

"Treasury takes very seriously all threats against our systems, and the data it holds," the spokesperson emphasized.

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