RICHMOND, Va. (AP) — An animal-rights group is suing after a public bus system in Virginia refused to display advertisements against animal testing.

The Richmond Times-Dispatch reported Thursday that the group is the Washington, D.C.-based White Coat Waste Project.

Its ad shows dogs peeking out from behind bars and demands that the "McGuire VA Medical Center: Stop Taxpayer-Funded Dog Experiments." The medical center has conducted research into cardiac health in humans. Some of the tests are considered extremely painful to the dogs.

The Greater Richmond Transit Company prohibits political ads on its buses. And a spokeswoman for the agency said the group's ad violates that rule.

The group's lawsuit, filed in federal court, claims the rule violates its constitutional rights and allows the government to pick and choose what views people can express.

___

Information from: Richmond Times-Dispatch, http://www.richmond.com