Chinese hackers broke into the computer networks of the U.S. Office of Personnel Management in March, The New York Times reported Wednesday, citing a senior official from the Department of Homeland Security.

The hackers reportedly gained access to some of the agency’s databases before the breach was detected and blocked by federal authorities. The Office of Personnel Management stores personal information -- list of foreign contacts, details of previous jobs and financial details -- of all federal employees, including those applying for top-secret security clearance. Although the attack was traced to China, it wasn’t immediately clear if the Chinese government was involved, the report stated.

According to the Times, a Homeland Security official confirmed that the attack had occurred but claimed that there had been no “loss of personally identifiable information.” He also added that an emergency response team had been set up to “assess and mitigate” any identifiable risks.

The disclosure of the attack comes at a time when U.S. Secretary of State John Kerry is in China for the sixth U.S. – China Strategic and Economic Dialogue.

The first successful hacking attack on a government network that was acknowledged by the U.S. occurred at the Department of Energy in 2013 when hackers gained access to confidential information of employees and contractors.

U.S. computer networks have been a frequent target of Chinese hackers and cyberattacks such as these have been a major source of diplomatic conflict between the two countries.

The U.S. has, in the past, accused the People’s Liberation Army of China of attempting to hack into sensitive government databases, including the office of the Secretary of Defense. In May, five officers of the Chinese military were indicted by the U.S. Justice Department for hacking into six American companies.

China, on the other hand, has pointed to evidence revealed by Edward Snowden, the former NSA contractor, which made public details about U.S. programs designed to intercept conversations of China's leaders and its military.