What is the American equivalent to the Canadian Security Intelligence Service?

The American equivalent to the Canadian Security Intelligence Service (CSIS) is the Federal Bureau of Investigation (FBI). While the FBI primarily focuses on domestic intelligence and law enforcement, it also has a role in counterintelligence and counterterrorism, similar to CSIS's mandate in Canada. Additionally, the U.S. Central Intelligence Agency (CIA) handles foreign intelligence gathering, complementing the FBI's domestic focus. Together, these agencies form the backbone of the U.S. intelligence community.