U.S. Treasury Secretary Janet Yellen met virtually on Monday with Chinese Vice Premier He Lifeng and raised concerns about "malicious cyber activity" carried out by Chinese state-sponsored actors, the Treasury Department said in a statement.

US Treasury Secretary Janet Yellen told China’s Vice Premier He Lifeng of her “serious concern” regarding “malicious cyber activity” a week after the US said Chinese state-sponsored hackers had breached the Treasury Department’s computer networks.

In a virtual meeting with Chinese Vice Premier He Lifeng, Yellen “expressed serious concern about malicious cyber activity by PRC state-sponsored actors,” the Treasury said in a statement, referring to the People’s Republic of China. Yellen also flagged the impact of such issues on the US-China relationship, the statement said.

Threat actors entered Treasury Department systems through BeyondTrust. The breach may be related to the Salt Typhoon attacks.

Liu Pengyu, a spokesperson for the Chinese Embassy in Washington, D.C., denied the U.S. government’s attribution of the cyberattack to the Chinese government, arguing that the United States did not present evidence of its claims.