PHILADELPHIA (AP) -- The Philadelphia 76ers will partner with Comcast Spectacor, their current landlord, to build a new arena in South Philadelphia and abandon a deal with the city to move downtown.

The stunning reversal comes as a relief to critics of the plan to put a $1.3 billion arena near City Hall at the edge of Chinatown. Mayor Cherelle Parker on Monday called the proposal "a win, win, win, win for Philadelphia."

"Philly, this is a lot. This is a curveball that none of us saw coming, but nevertheless, we are here," Parker said at a midday news conference.

However, some critics and city council members felt betrayed after two years of fraught negotiations over the downtown plan. City council member Jim Harrity told a news station he felt "completely bamboozled."

Parker was joined Monday by NBA Commissioner Adam Silver, who appeared remotely, and team and Comcast leaders who promised the new plan would bring vibrancy and a new vision to both locations. The parties also pledged to work with the city to try to bring a WNBA team to Philadelphia.

"Though plans have changed, the one thing that has not changed is our commitment to do something good for the Sixers, our fans and most importantly, our city," said David Adelman, a partner in the 76ers ownership group, Harris Blitzer Sports & Entertainment.

The city council had voted only weeks ago to approve the team's plan to open its proposed 76 Place downtown by 2031, despite opposition from residents of the city's nearby Chinatown and others. The team, which shares space with the Philadelphia Flyers of the NHL in an arena owned by Comcast, had said it wanted to own its own facility when its lease expired.

But the rival sides started talking two weeks ago before looping in city leaders in the high-stakes talks over the past three days.

The team, whose ownership group is led by investor Josh Harris, said it had formed a 50-50 joint venture with Comcast to replace its arena in the South Philadelphia stadium district by 2031. Comcast will also take a minority stake in the team and work together on the WNBA bid, the parties said in a joint statement Monday.

And they pledged to invest in the abandoned site, Market East, a once-bustling downtown retail corridor that has struggled for many years despite repeated attempts to revive it.

The partners, who also own the NHL's New Jersey Devils and have a controlling interest in the NFL's Washington Commanders, had vowed not to seek any city subsidies for the downtown project, which they said would reap $2 billion in economic growth for Center City. They did not immediately disclose financial terms of the new project.

Chinatown activist Vivian Chang said the community was cautiously optimistic, but troubled that "our city was held captive by the developers" and lost time it could have spent on other pressing issues.

"We have been saying all along that they were playing people," Chang told The Associated Press. "These billionaire developers didn't have anyone's interests in mind, in terms of the community. They just had their profits in mind."

Economist Victor Matheson, a College of the Holy Cross professor who studies stadium financing issues, said it's not unusual for team owners to change course as they hunt for the best deal. Last year, in Washington, the NBA's Wizards and the NHL's Capitals decided to stay in the city after a deal to move to the northern Virginia suburbs, with $515 million in public financing, imploded.

"This happens all the time," Matheson said, noting that the 76ers "played New Jersey against Philadelphia" in the hunt for public subsidies.

He believes the team planned to "pick up some subsidies along the way, and then when that didn't happen, they ended up of course back where they started."

Supporters of the downtown plan had hoped a glitzy, 18,500-seat arena would be the catalyst to revive Market East, which runs for eight blocks from City Hall to the Liberty Bell. "The way they reached this decision reflects a profound lack of respect for city leaders, stakeholders, and residents," council members Jamie Gauthier and Rue Landau said in a statement. "It was shameful for 76DevCo to pit working-class Philadelphians against one another and pressure city council to consider a half-baked proposal on an artificially rushed timeline."