Knicks fans flooded the streets around Madison Square Garden on Monday night after New York swept the Cleveland Cavaliers to advance to the NBA Finals for the first time in 27 years.  

Fans poured onto Seventh Avenue and the surrounding blocks after the Game 4 win, with some waving brooms to celebrate the sweep. One fan was seen hoisting an American flag from the top of the Garden while crowds danced in the streets below.

The NYPD said six people were taken into custody and issued criminal court summonses outside the Garden and Radio City Music Hall.

Monday’s celebrations came just days after the NYPD announced it would no longer support outdoor watch parties outside the Garden because of safety concerns tied to large crowds.

That announcement followed Thursday night’s Eastern Conference finals watch party, when police estimated 6,000 people packed the area around West 33rd Street and Seventh Avenue.

In a statement, an NYPD spokesperson said officers had been seeing “progressively more problematic issues” at watch parties outside the Garden.

The spokesperson said some fans jumped barriers, blocked traffic on West 33rd and 34th streets and Seventh Avenue, climbed on top of subway entrances and threw objects, including glass bottles, into the crowd Thursday night.

“The NYPD will not support more watch parties outside the stadium, but we will continue to review requests to support parties at alternate sites like SummerStage,” the statement said. “This is not about having enough of the unruly fans — this is about keeping people safe.”

Despite the decision, enthusiasm surrounding the Knicks’ postseason run has remained high across the city.

More than 13,000 fans packed Madison Square Garden for a sold-out indoor watch party as the Knicks defeated the Cleveland Cavaliers in Game 3 of the Eastern Conference finals.

“The energy in this arena is like the best energy I’ve ever experienced in a basketball game ever,” one fan told NY1. “I’ve never been to a Knicks game live. This is the closest I’ve gotten, and this is amazing.”

On Monday night, about 5,000 fans gathered at Radio City Music Hall for another sold-out watch party. Police maintained a visible presence outside the venue.

Some fans said they understood the NYPD’s safety concerns, but hoped outdoor celebrations would eventually return.

“It’s a great way to keep the community close,” one fan said. “To have the people of New York City, New Jersey and the tri-state area celebrate our Knickerbockers, I think it’s a special thing.”