One man was detained Thursday after he punched another man outside U.S. Bank Arena in Cincinnati as President Donald Trump held a rally inside.

Video of the altercation on the corner of East Pete Rose Way and Broadway was posted to Facebook and shared with The Cincinnati Enquirer.

Scott Fantozzi witnessed the incident and captured the video, saying it appeared the two men were arguing about politics.

The video shows one man exiting a Ford truck and punching the other man. It was unclear from the video what led to the altercation.

Cincinnati police officers responded within seconds and detained the man who had thrown punches.

As he was led away by police, the crowd started chanting: "Lock him up, lock him up."

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