Operation Yellowbird or Operation Siskin was a British Hong Kong–based operation to help the Chinese dissidents who participated in the Tiananmen Square protests of 1989 to escape arrest by the Chinese government by facilitating their departure overseas via Hong Kong. Western intelligence agencies such as Britain's MI6 and the U.S. Central Intelligence Agency (CIA) were involved in the operation. Other contributors included politicians, celebrities, business people and triad members from Hong Kong—forming the "unlikely" alliance which sustained the operation for most of its duration.