The use of so-called less-lethal munitions was authorized at 8 p.m. following reports of a small group of “violent individuals” throwing large pieces of concrete at officers, police said. A citywide tactical alert was issued shortly thereafter.

Chaos erupted earlier in the day in the heart of the Fashion District after federal immigration authorities detained employees inside a clothing wholesaler, and used flash-bang grenades and pepper spray on a crowd protesting the raid around 1:30 p.m.