A senior US Federal Bureau of Investigation (FBI) official has made an unusually public request to the hacking group ShinyHunters, telling the cybercriminals on Tuesday to get in touch following a wide-ranging breach of the bureau's job site.

In a video message posted on X on Tuesday, FBI Assistant Director Brett Leatherman, who leads the bureau's Cyber Division, said the recent arrest of a Dutch man in connection with the ShinyHunters investigation should serve as a warning.

"Other groups believed anonymity ​or their friends would protect them, and they were wrong," said Leatherman. "You know how to find us, and we know how to find you. I suggest you reach out first while the choice ​is still yours."

Although couched as a threat, Leatherman's request to open a channel of communication between law enforcement and the hackers is the latest indication of just how seriously the bureau is taking the incident, which has compromised sensitive medical records, Social Security numbers, family information and intelligence-related details of named FBI staffers.

An internal FBI memo circulated among employees said officials were operating under the assumption that every employee had been exposed.

ShinyHunters initially gave the bureau a week to retract an advisory about the hackers that the group took exception to, a period that expired on Tuesday. The hackers have since said the ultimatum was not a deadline or a threat and that they had no intention of publishing the data.

"This was all a marketing campaign," the group ​said on Monday.

'One of the worst breaches'

ShinyHunters said on September 22 that it had breached FBI systems and stolen information belonging to a huge number of current and former employees, claiming it had stolen data on "almost all" FBI agents and individuals who had applied for jobs with the agency. As evidence, it shared a screenshot of a vandalized FBI job site and what it described as a sample dataset containing information on about 5,000 agents.

The New York Times said the incident "is emerging as one of the worst breaches of sensitive government information."

BBC News also reported that current and former FBI agents had expressed shock, fear and anger following the hack.

Cybersecurity experts warned that such an attack could have long-lasting consequences. Cynthia Kaiser, a former FBI official and now senior vice president at cybersecurity firm Halcyon, said breaches like those claimed by ShinyHunters were "incredibly harmful" because they could be used by criminals to expose and put pressure on the people investigating them.

She noted that an old leak dating back to 2016 was still occasionally used to harass FBI agents. "Once that information is stolen, it is used forever."

ShinyHunters is regarded as one of the world's most notorious and attention-seeking hacking crews.

Its recent break-ins include the purported theft of millions of business records from video game developer Rockstar Games, the maker of "Grand Theft Auto," and a May intrusion centered on education tool Canvas that caused widespread disruption across US schools. Earlier this month, AI company Anthropic said it had caught ShinyHunters-linked hackers trying to use its tools.

(With input from Reuters)