The United States and China have reached an agreement on guidelines for requesting assistance on cybercrime and other malicious online activities.
The agreement was reached in talks in Washington this week among officials including US Attorney General Loretta Lynch, US Department of Homeland Security Secretary Jeh Johnson and Chinese Public Security Minister Guo Shengkun.
"These guidelines will establish common understanding and expectations regarding the information to be included in such requests and the timeliness of responses," the US said.
A 'hotline' will be developed to escalate issues that may arise in responding to cybercrime, and both sides have agreed to co-operate on cases of cyber-enabled crimes like child exploitation, theft of trade secrets, fraud and misuse of technology and communications for terrorist activities, and to enhance exchanges on network protection.
In a statement, the US Justice Department said along with the guidelines, China and the US will conduct "tabletop exercises" in the spring with a number of scenarios designed to improve cooperation.
The two nations agreed to increased cooperation on a case-by-case basis for a range of cybercrimes, including child exploitation, theft of trade secrets, fraud and activities relation terrorism.
There was also an agreement for further high-level talks on cybersecurity, including the possibility of establishing a cybercrime "hotline".
The talks had long been planned to follow a landmark agreement between the two countries reached in September. The next round will come in June, the Justice Department said.
China's Ministry of Public security said the agreement would have a "major impact" on the implementation of internet security measures, adding that the two sides resolved to maintain frank discussion on the issue.
The statement made no mention of a report from China's Xinhua news agency this week on the hacking of sensitive personnel records on people holding US security clearances at the Office of Personnel Management (OPM) last year. Xinhua said the hacking was criminal, not state-sponsored.
The Washington Post reported Wednesday that multiple people had been arrested in that case, which compromised data on more than 22 million federal workers.
However, well-placed sources said they believed it was a legitimate intelligence target and a government-sponsored intrusion.
US officials have said they are unaware of any evidence demonstrating that the hacked OPM data had been used for any nefarious purposes.