With much fanfare, Microsoft Corp. opened a development and innovation hub at the University City Science Center in June 2016 to attract software developers, corporate partners, and entrepreneurs to Philadelphia.

Now the hub is closing, officials confirmed Friday.

The Microsoft Reactor Philadelphia — one of only three in the nation — hosted about 100 programs with 3,200 participants over its 15-month existence. Its departure is a setback for a city seeking to modernize its economy with a vibrant high-tech sector.

Microsoft spokesman Curtis Lee said Friday that the Reactor will close because of a corporate restructuring, but the company will remain active with the Science Center and its partners, promoting skills for women and minorities and supporting entrepreneurs and tech companies in Philadelphia.

The Reactor programs in New York and San Francisco will continue unchanged, Lee said.

In a tweet on Friday, Microsoft's Amanda Lange said: "We're really proud of the work we did at the Philly Reactor. I'm still in Philadelphia so I personally haven't gone anywhere." Her title was Microsoft tech evangelist at the Reactor.

Science Center spokeswoman Kristen Fitch said the first-floor Reactor is being marketed for a new tenant. "We hope to share news of a new tenant soon," she said. Quorum, which the Science Center describes as an "entrepreneurs clubhouse," will remain open on the Science Center's eighth floor.

She added that "while we are disappointed by Microsoft's decision to close the Reactor, we are proud of the program's achievements and will be building on them." She was referring mostly to the programs and participants.

Mayor Kenney attended the formal launch of the Microsoft operation in November. His office said on Friday that he did not have advance warning of Microsoft's decision. "We are grateful to Microsoft for the services they offered at the Reactor and look forward to their continued presence in Philadelphia, even if it comes in a slightly different form," a spokeswoman said in a statement.

The Reactor closing was first reported by online publication Technical.ly Philly, which covers the regional tech sector.

Philadelphia has an opportunity to grow its tech sector as Center City attracts tech- and smart phone-savvy millennials, many believe.

At the same time, boosting Philadelpia's tech sector has gained urgency with Comcast Corp.'s plans to open in 2018 its new tech center — now under construction — near the corporate headquarters at 17th and Arch Streets. The company has said it will need to hire large numbers of engineers and software developers and expects many of them to acquire necessary skills at local tech companies.