A group of St. Paul parks advocates are suing the city, saying officials broke their promise to turn a downtown parcel into a public park.

At issue is tiny Pedro Park, which sits on 0.45 acres along E. 10th Street that the Pedro family donated to the city in 2009. While the city had planned to demolish the adjacent Public Safety Annex to create a larger park, officials have instead opted to sell the parcel to a developer.

In a lawsuit filed last month in Ramsey County District Court, St. Paul residents Kati Ann Berg and Gary Everett Stoos joined with Marilyn Gerene Pitera of the Pedro family to demand that the city fulfill its pledge to build a larger park. Friends of Pedro Park Expansion, a group of residents fighting against the city’s plans, are raising money for the suit.

The plaintiffs, who are representing themselves, argue that the city is violating its comprehensive plan and multiple ordinances — as well as its promise to the Pedro family and residents who moved downtown to live near the planned park — by selling the Public Safety Annex land to a developer.

St. Paul leaders are working with the Minneapolis-based Ackerberg Group on plans for the parcel. The deal would likely include money from Ackerberg to revamp and operate the existing park space.

Design advisory committee meetings in May and June resulted in two preliminary designs for a revamped Pedro Park, with more open space, water features and spots for dogs to play. Several people resigned after the committee’s May 24 meeting, saying they weren’t given a chance to discuss the park expansion.

City officials were not immediately available to comment on the suit.