The white nationalist group is one of the largest neo-Nazi organizations in the United States and is known for anti-Jewish and racist protests.
Images show LGBT supporters attempting to block them joining the event. Police are seen in the vicinity.
Motor City Pride began at noon and had four stages of entertainment, in addition to over 100 food stalls and other merchandise on sale. The city's main parade takes place on Sunday.
One image of the day's events appears to show an unidentified neo-Nazi group member urinating on an Israeli flag, with one LGBT supporter watching in horror at his actions.
Counter-protesters were pictured being blocked by law enforcement from intervening as members of the National Socialist Movement demonstrated.
Thousands of people, many in colorful costumes, kicked off 2019 Motor City Pride Festival weekend on Saturday amid rainbow flags in downtown Detroit's Hart Plaza.
Described on its website as Michigan's largest pride celebration, the event is estimated to have been attended 40,000 people celebrating the LGBTQ+ community.
However the day's celebrations took a sour turn when the NSM showed up and amplified tensions among the LGBT community.
Until 2007, NSM members protested in full Nazi uniforms, and traded in their look for black 'Battle Dress Uniforms,' according to their website.
The group was founded in 1994 in Michigan, claiming that it 'specializes in theatrical and provocative protests' and is one of the largest and most prominent neo-Nazi groups in the United States.
The resurgence of the NSM began in 2004, in the wake of the deaths of the country’s two major neo-Nazi leaders, William Pierce and Richard Butler.
Unlike other neo-Nazi outfits, the NSM adopted an open-arms recruiting policy that allowed members of other white supremacist groups to participate in NSM actions and join the NSM.