YICHANG, China — Behind a large glass wall, a worker in full protective gear watches as hundreds of tiny glass bottles whizz by every minute, sterilized, filled and packaged by a ballet of robotic arms.

Inside each ampule is the substance at the heart of the geopolitical strife between the United States and China: fentanyl, the deadly opioid set to be top of the agenda when Presidents Donald Trump and Xi Jinping meet Thursday.

NBC News got exclusive access to the headquarters of Yichang Humanwell Pharmaceutical, the largest producer of the drug in China, and indeed Asia, at its sprawling complex in the central city of Yichang.

Humanwell says that it only supplies fentanyl for use in hospitals and that it does not export any medication to the United States, Mexico or Canada. In 51 years

See Full Page