Tuscaloosa: A towering Baby Trump protest balloon was knifed and deflated by someone unhappy with its appearance during President Donald Trump's Saturday trip to Alabama, organisers said.

The incident occurred during Trump's visit to watch the University of Alabama football game. The six-metre tall balloon was set up in a nearby park.

A responding officer and an unidentified man stands by the deflated Baby Trump balloon that was knife in Tuscaloosa, Alabama. Credit:AP

Jim Girvan, the organiser of a group that "adopts" out Baby Trump balloons for protests, said a man charged the balloon with a knife and cut a 2.4-metre gash in the back. Girvan said the unidentified man was taken into custody. Tuscaloosa police said in a statement that a 32-year-old local man was charged with criminal mischief in the incident.

The orange, diaper-clad, cellphone-clutching caricature of the president is often taken to Trump appearances as a way to protest him.