Taiwan pursued a number of weapons of mass destruction programs from 1949 to the late 1980s. The final secret nuclear weapons program was shut down in the late 1980s under US pressure after completing all stages of weapons development besides final assembly and testing. Taiwan lacked an effective delivery mechanism and would have needed to further miniaturize any weapon for effective use in combat. Currently, there is no evidence of Taiwan possessing any chemical, biological, or nuclear weapons.[1][2] However, nuclear weapons from the United States were deployed to Taiwan during a period of heightened regional tensions with China beginning with the First Taiwan Strait Crisis and ending in the 1970s.[3][4][5]