British officials say the names and bank details of thousands of serving British soldiers, sailors and air force members have been exposed in a data breach at a payroll system.
The Ministry of Defense said Defense Secretary Grant Shapps would make a statement in the House of Commons on Tuesday afternoon "setting out the multi-point plan to support and protect personnel."
The ministry would not comment on a Sky News report that Chinese hackers are suspected of carrying out the cyberattack.
Cabinet Minister Mel Stride told Sky that "we are not saying that at this precise moment."
British media reported that the government will blame "hostile and malign actors" but will not name the country it believes is responsible.
The breach occurred at a third-party payroll system holding bank details of all serving armed forces personnel and some veterans. In a few cases, addresses may also have been exposed.
So far, investigators have found no evidence that data have been removed.
In March, Britain and the United States alleged that hackers linked to the Chinese government had targeted U.S. officials, journalists, corporations, pro-democracy activists and the U.K.’s election watchdog in a campaign of "malicious" cyberattacks. The two countries imposed sanctions on several individuals and the U.S. charged seven alleged hackers, all believed to be living in China.