5.6 million fingerprints stolen in OPM hack: What can thieves do with data?

The millions of fingerprint images stolen in one of the US government’s biggest data breaches could help Chinese intelligence identify American spies abroad, federal officials say.

On Wednesday, the Office of Personnel Management announced that the number of people whose security clearance data had been stolen is now believed to be 5.6 million, five times the original size of the breach. Authorities believe the hack may have been carried out by a Chinese operation, affecting around 21.5 million current and former federal employees or job applicants.

Experts say “the theft could give Chinese intelligence a huge leg up in recruiting informants inside the U.S. government,” reports The Associated Press. Forms provided by the employees include identifying information about friends and family in the US and abroad, which could save the Chinese years of intelligence gathering on its recruitment process.

Though the White House has not publicly blamed China for the attack, US national security advisor Susan Rice warned China on Monday that government-authorized cyber espionage must stop.

"This isn't a mild irritation, it's an economic and national security concern to the United States," said Ms. Rice as she delivered remarks at George Washington University, according to Reuters. “It puts enormous strain on our bilateral relationship, and it is a critical factor in determining the future trajectory of US-China ties.”

The warning came days ahead of Chinese president President Xi Jinping's first state visit to the White House on Thursday, where he and President Obama are expected to discuss climate change and human rights issues, according to The New York Times.

Despite Rice’s earlier warning, White House spokesman Josh Earnest said on Wednesday he did not "have any conclusions to share publicly about who may or may not have been responsible."

Intelligence officials have downplayed the danger posed by the breach, and even called it “a fair intelligence target, one the U.S. would pursue if it had the chance,” reported the AP.

The hack has cost the agency director her job. Intelligence officials say the full extent of damage will be determined over the course of years and may never be fully revealed to the public.

This report contains material from The Associated Press and Reuters.