The International Spy Museum, a popular private attraction in the District, would relocate to the former Carnegie Library in Mount Vernon Square under a plan by D.C. officials.

Events DC, which manages the District’s convention and sports business, announced Monday that it planned to renovate and expand the historical library building by moving the Spy Museum to the library’s underground space and building a “sculpted glass pavilion” on the north side of the building that would house a visitors center, café and the Spy Museum store.

Events DC, run by president and chief executive Gregory O’Dell, also plans to add outdoor seating, an amphitheater and a playground around the building. Events DC and Malrite, the Cleveland-based museum owner, would serve as co-developers of the project. The Historical Society of Washington would keep its offices in the building as well.

In all, the project would add 58,000 square feet to the property, but the idea requires approval from local and federal stakeholders because of the historical nature of the grounds and library building, which was completed in 1903 and served as the city’s central library until 1970. The centerpiece of Mount Vernon Square, the Carnegie Building was one of thousands of libraries built nationwide with funds donated by steel tycoon and philanthropist Andrew Carnegie.

O’Dell said he spoke with staff from some of the agencies that will consider the idea, among them the National Capital Planning Commission, the Commission on Fine Arts and the Historic Preservation Review Board, and got some positive feedback. “They were clear that nothing that they said or did would represent what the formal commission or board would say, but they at least gave us ... advice as to what the process would be,” he said.

For 11 years, the Spy Museum has been located at 800 F St. NW, in the heart of what is now one of the city’s most bustling and lively neighborhoods. But Jason Werden, a spokesman for the museum, said it was running out of room. “It’s been a great place for us since our inception, but we’re at a fortunate place now where we need more space,” he said.

The Carnegie plan, Werden said, also offered long-term stability in a growing part of the city. Founder Milton Maltz and his wife, Tamar, would convert the operation to a nonprofit, and the city would hold seats on the board. “It’s going to be an opportunity for he and his wife to take a step back,” Werden said.

A number of years remain on the museum’s lease with its landlord, Douglas Development, but Norman Jemal, principal at the firm, said he expected there would be excellent demand to replace the museum should it relocate. Retail rents in the neighborhood have been spiking, sometimes beating those in Georgetown. “Should they leave, there is much more upside than downside,” he said.