The brief confrontation came on Saturday at the end of a peaceful march by thousands against the environmental impact of the Games and the presence of US agents in Italy.
Police held off the violent demonstrators, who appeared to be trying to reach the Santagiulia Olympic ice hockey rink, after the skirmish. By then, the larger peaceful protest, including families with small children and students, had dispersed.
Earlier, a group of masked protesters had set off smoke bombs and firecrackers on a bridge overlooking a construction site about 800 metres from the Olympic Village that's housing around 1500 athletes.
Police vans behind a temporary metal fence secured the road to the athletes' village, but the protest veered away, continuing on a trajectory toward the Santagiulia venue. A heavy police presence guarded the entire route.
There was no indication that the protest and resulting road closure interfered with athletes' transfers to their events, all on the outskirts of Milan.
The demonstration coincided with US Vice President JD Vance's visit to Milan as head of the American delegation that attended the opening ceremony on Friday.
He and his family visited Leonardo da Vinci's The Last Supper closer to the city centre, far from the protest, which also was against the deployment of US Immigration and Customs Enforcement agents to provide security to the US delegation.
US Homeland Security Investigations, an ICE unit that focuses on cross-border crimes, frequently sends its officers to overseas events like the Olympics to help with security.
The ICE arm at the forefront of the immigration crackdown in the US is known as Enforcement and Removal Operations, and there is no indication its officers are being sent to Italy.
At the larger, peaceful demonstration, which police said numbered 10,000, people carried cardboard cutouts to represent trees felled to build the new bobsled run in Cortina.
"Let's take back the cities and free the mountains," read a banner by a group calling itself the Unsustainable Olympic Committee.
"They bypassed the laws that usually are needed for major infrastructure project, citing urgency for the Games," said protester Guido Maffioli, who expressed concern that the private entity organising the Games would eventually pass on debt to Italian taxpayers.
Homemade signs read "Get out of the Games: Genocide States, Fascist Police and Polluting Sponsors," the final one a reference to fossil fuel companies that are sponsors of the Games.
The demonstration followed another last week when hundreds protested the deployment of ICE agents.
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