China has 'killed or imprisoned at least a dozen US spies in two years'

China has reportedly killed or imprisoned at least 20 US intelligence assets in the country since 2010, destroying years worth of intelligence efforts in the country

American officials, current and former FBI officials told The New York Times that one operative was allegedly shot and killed in front of his colleagues as a warning against spying. Several other were imprisoned.

US officials described the losses as “one of the worst” intelligence breaches in decades, comparing it to the number of assets lost in the Soviet Union in the 1980s and 90s, when two prominent US assets worked as double agents for the Soviets. Officials said the breach has destroyed years of network-building within the country.

In 2010, American intelligence-gathering in China was said to be the best it had been in years. But by 2011, US officials realised their sources in the country were slowing drying up. As a result the CIA and FBI launched a joint investigation into almost every operation in Beijing in an attempt to determine the cause.

The investigation is said to have honed in on one man, a former CIA operative living in China, who intelligence officials believe could have been leaking to the Chinese government. However, the US agencies never uncovered enough evidence to convict him.

Another suspect, a Chinese-American who left the CIA several years ago, has denied any wrongdoing. The CIA’s top spy hunter, Mark Kelton, is said to be resistant to accusing anyone of espionage without “iron clad evidence”.

Some members of the investigation, however, are convinced that the breach is the result not of a mole, but of a compromised communications system. They believe the US’s encrypted method of communicating with operatives abroad has been hacked by the Chinese.

The news of the breach comes as the US investigates several intelligence breaches, including one allegedly stemming from China in 2015. That year, hackers accessed the personal data of at least four million current and former government employees, including social security numbers.

Much of the discussion in the US, however, has centred around Russian intelligence breaches. In 2014, suspected Russian hackers compromised the White House and State Department email systems. During the 2016 presidential election, Russian hackers accessed – and published – emails from the Democratic National Committee.

But officials say China has been “particularly aggressive” in its espionage efforts in recent years, both before and after 2015. In 2016, for example, a longtime FBI employee with top-secret clearances plead guilty to providing the Chinese government with information. Just this March, longtime State Department employee Candace Marie Claiborne was arrested for “concealing extensive contacts” with Chinese officials.

The FBI has previously warned of Chinese officials attempting to recruit American college students as spies.

US President Donald Trump has recently softened his stance on China, reneging on a promise to label the country a “currency manipulator” and inviting the Chinese President to a weekend retreat at his Palm Beach estate. Mr Trump has called the country a key ally in containing the threat posed by North Korea.