Estonian Internal Security Service (ISS)

While the provided articles don't explicitly mention the Estonian Internal Security Service (ISS), their involvement can be inferred. The ISS, Estonia's primary counterintelligence and internal security agency, is responsible for protecting the country's constitutional order, preventing and combating terrorism, and safeguarding state secrets. The recent incident involving a drone originating from Russia striking the Auvere power plant near the border falls squarely within the ISS's purview. The agency would likely be investigating the drone's origin, purpose, and potential links to hostile actors. The incident's proximity to the Russian border and the targeting of critical infrastructure elevates the security concerns, making the ISS's investigation crucial for assessing the threat level and implementing appropriate countermeasures to prevent future incidents and protect Estonia's energy security and overall national security.