Ms Cooper will highlight that these 'hybrid threats' are designed to weaken critical national infrastructure, undermine interests, and interfere in democracies, particularly by using AI and manipulated videos to erode support for Ukraine.
Her warning follows a mini-summit led by Sir Keir Starmer with European leaders, including President Zelensky, to discuss Ukraine's future and counter concerns over a US-backed peace proposal.
The UK experienced approximately 7.8 million cyber attacks last year, with many originating from hostile states like Russia, China, and North Korea, causing significant economic and social damage.
Cooper will emphasise that the issue is not about legitimate free speech but about foreign states using social media to sow division and advance their own interests.