A mass cyberattack on Britain's military has exposed the names and banking details of thousands of British soldiers, officials said Tuesday.

Prime Minister Rishi Sunak and Defense Minister Grant Shapps said there were indications that a "malign actor" was responsible for the attack.

"I do want to reassure people that the Ministry of Defense has already taken the action of removing the network offline and making sure that people affected are supported in the right way," Sunak said.

Neither Sunak nor Shapps named China as the culprit, but the BBC and other British media outlets reported that Chinese hackers are suspected of being responsible for the breach.

"We cannot rule out state involvement," Shapps told the House of Commons. But he did not single out China.

However, Labour Party defense spokesperson John Healey wanted to know why "the media has clearly been briefed that China was behind" the attack conducted on a third-party payroll system that contained the information for as many as 272,000 armed forces personnel.

Shapps said British officials took the system offline "immediately" and began an investigation into the attack and SSCL, the contractor hit by the cyberattack. He said there was "no evidence that any data had been removed."

Tobias Ellwood, a British lawmaker and the former chairman of a parliamentary defense committee, singled out China as the likely culprit.

"Targeting the names of the payroll system and service personnel's bank details — this does point to China because it can be as part of a plan, a strategy to see who might be coerced," Ellwood told BBC radio.

'Our eyes are wide open'

In southeast London, Sunak said that his government has established a "robust policy" toward China, which has become increasingly "authoritarian" at home and "more assertive" abroad.

"Our eyes are wide open when it comes to China," Cabinet minister Mel Stride told Sky News television without laying blame on China for the breach.

China has vehemently denied responsibility for the attack.

"Utter nonsense" is how China's Foreign Ministry spokesperson Lin Jian described the notion that China is responsible for the breach. "China has always firmly opposed and cracked down on all types of cyberattacks."

The spokesperson also said British politicians' comments blaming China for the attack were "absurd."

China calls accusation 'slander'

In March, Britain and the United States accused hackers linked to China's government of conducting a global campaign of "malicious" cyberattacks on U.S. officials, journalists, pro-democracy activists and corporations and Britain's election watchdog.

Both countries placed sanctions on several people. The U.S. charged several hackers who are believed to reside in China.

China called the accusation that it was responsible for the attacks "malicious slander."