CHRISTIANSBURG -- Developers planning to build a "big-box" retail store such as a Wal-Mart in Blacksburg struck back Thursday at a proposed government ordinance that could curb their project.

Fairmount Properties of Ohio and Blacksburg-based companies Llamas LLC and Diversified Investors LLC filed suit against the town, including its elected council and zoning administrator Steve Hundley, in Montgomery County Circuit Court.

The lawsuit asks the court to protect the companies' rights to build a 186,000-square-foot retail store behind Margaret Beeks Elementary School without retroactive government interference.

The town council approved a rezoning last year that cleared the way for a 40-acre revitalization project along South Main Street. But after the developers submitted site plans showing a big-box retail store in the project, Councilman Don Langrehr proposed ordinance 1450: a governmental move that would limit the size of retail buildings in town to 80,000 square feet. Larger buildings could then be built only with the council's approval of a special use permit.

Last month, the council decided to fast-track consideration of the ordinance and is set to hear public comment and vote on it May 29.

Support for the ordinance has been growing. Dozens of residents opposed to Wal-Mart and other big-box stores have asked the planning commission and the council to pass the ordinance, in hopes that it will stop that part of the South Main development. A newly formed group, Blacksburg United for Responsible Growth, has orchestrated an e-mail blitz, a public protest and a petition drive.

The group has also consulted an attorney about ways the big-box part of the South Main plan might be stopped, according to Daniel Breslau, chairman of the group's steering committee. But at this point there is no reason for the group to take its own legal action, he said.

The developers' suit asks the court to rule on whether last year's rezoning and subsequent town reviews of some of their project plans protect them from the provisions of ordinance 1450.

It requests that the court issue a writ of mandamus compelling the town's planning and engineering department to review final site plans for the South Main project before May 29. Courts may order such writs to compel public officials to perform an official duty.

Town Manager Marc Verniel said Thursday that under town code and state law Blacksburg has 60 days to review and rule on the site plans. He also pointed out the South Main plans are "massive" and will require a lot of time to properly review.

But the developers argue in their suit that the town's stated policy promises a review within 15 days. The suit also asks that the developers be compensated for their legal fees and "such other relief as may be proper."

Mayor Ron Rordam could not be reached for comment Thursday.

Town Attorney Larry Spencer declined to comment on the suit until he meets with the council at a Tuesday meeting. Under normal circumstances, the town would have 21 days to respond to the complaint, Spencer said.

But Jim Cowan, an attorney representing the developers, said his clients plan to file a motion asking the court to expedite the case.