When the U.S. military aide carrying the nuclear football entered the Great Hall, Chinese security officials blocked his entry. (The official who carries the nuclear football is supposed to stay close to the president at all times, along with a doctor.)

A U.S. official hurried into the adjoining room and told Kelly what was happening. Kelly rushed over and told the U.S. officials to keep walking — “We’re moving in,” he said — and the Americans all started moving.

Then there was a commotion. A Chinese security official grabbed Kelly, and Kelly shoved the man’s hand off of his body. Then a U.S. Secret Service agent grabbed the Chinese security official and tackled him to the ground.