U.S. officials said Tuesday they had not expelled Chinese hackers from telecommunications companies, warning concerned users to turn to encrypted messages.

China-linked spies are still lurking inside U.S. telecommunications networks roughly six months after American officials started investigating the intrusions, senior officials told reporters Tuesday.

The U.S. has been investigating the Salt Typhoon hackers since late spring and early summer this year, a senior FBI official said.

Chinese hackers who penetrated U.S. telecoms likely haven't been fully evicted partially due to shifting tactics made in response to public disclosures, federal

T-Mobile says the Chinese "Salt Typhoon" hackers who recently compromised its systems as part of a series of telecom breaches first hacked into some of its routers to explore ways to navigate laterally through the network.

Salt Typhoon deployed various methods to break into telecommunications firms that went far beyond a singular run-of-the-mill credential-stealing attempt, according to a person familiar.

US officials are still trying to help major telecom providers evict Chinese government-backed hackers from their networks and don’t have a timeline for when that will be done, officials said Tuesday.

The group has been targeting 'Cisco-specific features' to help it break into US telecommunication networks, according to a new advisory from the FBI and CISA.