Which government agency is know for conducting counterintelligence activities?

The FBI is known for conducting counterintelligence activities because it is the principal federal agency responsible for investigating and preventing espionage and other forms of intelligence threats against the United States. The FBI's counterintelligence efforts focus on detecting, disrupting, and deterring foreign espionage efforts aimed at government, military, and economic entities. This includes investigating cases of spying by foreign nations and protecting sensitive national security information.

Although other agencies, like the National Security Agency, also engage in activities related to intelligence and counterintelligence, the FBI's unique position as a domestic law enforcement agency allows it to conduct broad investigations that encompass a variety of threats, including those from foreign intelligence services. The Department of State and the Treasury Department primarily focus on diplomatic and financial aspects rather than direct counterintelligence activities, which further underscores the FBI's specialized role in this field.