As China and Iran hunt for dissidents in the US, the FBI is racing to counter the threat

American officials say foreign countries like China and Iran intimidate, harass and sometimes plot attacks against political opponents and activists in the U.S. A series of cases brought by the Justice Department shows the frightening consequences that geopolitical tensions can have for ordinary citizens as governments historically intolerant of dissent inside their own borders are increasingly keeping a threatening watch on those who speak out thousands of miles away. The practice of governments harassing dissenters is known as transnational repression, and U.S. officials say there's been an alarming rise in cases. China denies that it engages in the practice.