The Metropolitan Council is fighting a court ruling requiring the regional planning body to hand over behind-the-scenes communications to a group opposing the Southwest light-rail project.

The Lakes and Parks Alliance sued the Met Council in 2014 in a bid to stop the line's path through the Kenilworth corridor in Minneapolis, a popular biking and pedestrian area.

In the legal battle being waged in U.S. District Court, the route's opponents sought documents including correspondence with elected officials, employees and would-be contractors.

The Met Council filed a protective order fighting the request, but that was overruled by Magistrate Judge Steven Rau earlier this month. Now, the Met Council has filed a formal objection to Rau's decision, calling it "contrary to law."

The $1.77 billion transit project — the costliest of its kind in state history — would link downtown Minneapolis to Eden Prairie, traveling through St. Louis Park, Hopkins and Minnetonka. It is expected to begin service in 2020.

The Lakes and Parks Alliance claims that the Met Council illegally limited its options to just one route — which involves sharing the Kenilworth corridor in Minneapolis with freight rail and the recreational trail through a series of bridges and tunnels.

U.S. District Judge John Tunheim is expected to rule on the Met Council's objection.

In a statement Monday, Met Council spokeswoman Kate Brickman said, "After reviewing the Met Council's actions last summer, Chief Judge Tunheim concluded the Met Council complied with state and federal law governing the environmental review of the SWLRT project.

"This small group of opponents now seeks to engage in a fishing expedition, hoping to find some new ground to undermine the proposed project which is supported by all the cities it will serve," she added. "This unprecedented attempt to revisit matters that have previously been ruled upon comes at a great cost to taxpayers."

In a statement, Lakes and Parks Alliance spokeswoman Mary Pattock said, "The Met Council is [again] trying to delay our lawsuit using the same argument the court has already denied three times! Why is it spending thousands of taxpayer money on attorneys to hide documents that belong to the public? One can only conclude that what they have to hide is illegal, embarrassing, or both."