The U.S. cyber watchdog agency CISA said Monday there was "no indication" the recently reported breach at the U.S. Treasury Department had affected any other federal agency.
Late last month the U.S. Treasury reported that an unspecified number of computers had been compromised by Chinese hackers following a breach at contractor BeyondTrust, which provides cybersecurity services.
BeyondTrust said last month that a limited number of clients were affected but has not elaborated.
"As the forensic investigation is ongoing, BeyondTrust is unable to confirm the other customers who may or may not have been impacted," the company said Monday in an email.
The Washington Post has reported that the hackers breached the U.S. Treasury office that administers economic sanctions, aiming to steal information about Chinese entities that the U.S. government might be considering designating for financial sanctions.
Republican lawmakers have demanded a briefing about the breach, which is the latest in a series of intrusions blamed on Beijing.
Liu Pengyu, spokesperson for the Chinese Embassy in Washington, has previously described the Treasury hack reports as "irrational" and represented "smear attacks" against China.