THE TRANSATLANTIC MAGAZINE
The combined action would address "evolving threats with a full range of capabilities", they said.
The shared adversaries were not named but the announcement follows increasing concern over Russia-based ransomware.
The plan was discussed last week at an annual meeting of intelligence chiefs, in the US.
Gen Sir Patrick Sanders and Government Communications Headquarters (GCHQ) director Sir Jeremy Fleming and US Cyber Command head Gen Paul Nakasone "reaffirmed" their commitment to jointly disrupt and deter new and emerging cyber-threats.
As democratic nations, the two countries were committed to carrying out proportionate and necessary operations within the law, they said.