CHICAGO (AP) — The head of the Chicago Park District says demands from a group suing to block Star Wars filmmaker George Lucas from building his museum on Chicago’s lakefront are “outrageous.”

Friends of the Parks released a memo recently outlining stipulations under which it would settle its lawsuit, including a legally binding promise from Chicago to protect the lakefront from development for the next century. The memo says the group also wants 5 percent of museum revenues allocated to parks improvements.

Chicago Park District Board President Jesse Ruiz on Sunday accused the group of deliberately attempting to sabotage the project.

The Chicago Sun-Times reports that Ruiz told the group in a letter that “attempts to demand money from the museum are nothing short of extortion.”