Activists suing the city over a deal to build a park in east downtown received a major blow Friday afternoon when a Hennepin County judge ordered them to post a $10 million surety bond.

The judge, Mel Dickstein, said that plaintiffs Paul Ostrow, Stephanie Woodruff and Dan Cohen must post the bond before next Thursday. But Ostrow acknowledged in an interview that that won't be possible, and they are exploring their appeal options.

"We think there are some clear factual errors and procedural errors in the court's decision," said Ostrow, an Anoka county prosecutor and former City Council president. "But whether there are issues that we can appeal, and how we might do that, is something that we have to determine."

The group had argued that only the city's Park and Recreation Board has the authority to own and operate a park. At issue is a 1.66 block park adjacent to the new Vikings stadium, which is the centerpiece of a $400 million development deal.

The city said the lawsuit was threatening the entire project. They requested the surety bond to cover any losses if the suit fails.

"Under the facts of this case, a surety bond should be required," Dickstein wrote. "The Court concludes (1) the present lawsuit challenges the City's authority to contractually bind the City to design, construct and maintain a park as part of its commitment to the Downtown East developer; (2) the City may suffer a loss from the mere pendency of this action; and (3) Plaintiffs are not likely to succeed on the merits."

Here is the judge's ruling:

Order Granting Motion SuretyBond 27-CV-13-21254 by eric_roper