Yahoo has become the latest tech firm to reveal how many requests for user data it has received from US government agencies.

In the six months to the end of May, the company received between 12,000 and 13,000 demands for information.

In a blog post, Yahoo CEO Marissa Mayer said the most common requests concerned fraud homicides, kidnappings, and other criminal investigations.

Tech firms have come under pressure to reveal how many national security related requests they receive, following disclosures around Prism, the highly classified US National Security Agency program that seizes internet company records.