The Scattered Castles system contains information that could be used to reveal covert operatives' real names. Reuters A database containing the classified personnel records of US spies may have been merged with the database of the Office of Personnel Management (OPM) before the latter was hacked, Shane Harris of The Daily Beast reports.

When administration officials asked intelligence agencies in 2010 to merge their records with OPM's, creating a unified security-clearance system, intelligence officials initially refused to comply.

They refused out of concern that combining Scattered Castles — the US spy-agency database — with OPM's database of federal employees could give hackers access to the identities of covert operatives if the massive OPM database ever suffered a breach.

By 2014, however, according to The Daily Beast, OPM security-clearance files were being uploaded into Scattered Castles' database, beginning a process of linking the databases.

"If there are connections between the two — as that recent government report suggests there are — it could be exploited by hackers, giving them a pathway from OPM into the most highly classified personnel records in the entire government," Harris reports.

US officials contacted by The Daily Beast denied that Scattered Castles was affected by the OPM hack, but they never said explicitly that the two databases were not linked.

"I have high confidence that the agencies do not have a clear understanding of the architecture of their systems and how they're interconnected," Michael Adams, who served more than two decades in the US Special Operations Command, told The Daily Beast.

Adams noted that because administration officials lacked this understanding, they could not say with certainty that the intelligence community's records were unaffected by the hack.

"I further believe that the US government either doesn't understand or is obfuscating the national-security implications of this cyberattack," he said. "These people either need serious help or need to come clean now."

Office of Personnel Management director Katherine Archuleta on Capitol Hill in Washington on June 16. AP If they were linked, then hackers who infiltrated OPM's database, stealing the sensitive security-clearance and background information of more than 18 million federal employees, were most likely able to steal the same information from the nation's spies.

The massive hack, allegedly perpetrated by the Chinese, was "classic espionage" on an unprecedented scale, a senior administration official told The New York Times.

Jeff Stein of Newsweek reported last week that the hackers who infiltrated OPM also breached FBI agents’ personnel files.

Joel Brenner, who from 2006 to 2009 served as the Intelligence Community's top counterintelligence official, described the hack to the Associated Press as "crown jewels material, a goldmine" for China, adding: "This is not the end of American human intelligence, but it's a significant blow."

The Theodore Roosevelt Federal Building that houses OPM headquarters seen June 5. Mark Wilson/Getty Images "I'm really glad to be out of the game," a recently retired CIA senior operations officer told former NSA counterintelligence analyst John Schindler in a Daily Beast article.

"There's bad, there's worse — and there's this," he said, referring to the breach. "CIA officers are not supposed to be anywhere in OPM files, but I'm glad I'm not posted overseas right now, hoping that's true."

Hackers who infiltrated OPM had access to the agency's security-clearance computer system for over a year, giving them ample time to steal as much information as possible from OPM's database of military and intelligence officials — and ample time to uncover a pathway to Scattered Castles, if such a pathway existed.