Operators of sightseeing vans who solicit passengers on and around the Mall are being called in by officials and told that they need official permits to stay in business.

It's caused something of a furor among 20-odd operators, some of whom have lobbied the mayor's office and their congressmen in an effort to get around the requirement. Gregory Paul Barth, general counsel of the Washington Metropolitan Area Transit Commission, which regulates the area's sightseeing services, said the situation began last fall when the U.S. Park Police issued tickets to two van operators who lacked the commission's special-operations certificates.

One of the accused operators, later enjoined by the U.S. District Court from flouting the licensing rule, contended that he was being punished for something being done flagrantly by 20 or more competitors.

That led Barth and a fellow official to tour the Mall area with Park Police and summon the van operators to the transit commission office for a briefing on how to come into compliance with the law. Those interviews began yesterday, Barth said.

"We're not trying to prosecute or issue real tickets," Barth said. "We're just putting them on notice and telling them we'll do everything we can to provide legal authority ," Barth said. Until permits are granted, however, the van operations must cease, he noted.

Getting a permit costs the price of a newspaper classified advertisement notifying of a permit application plus about $200 for a hearing transcript. Barth said taxicab operators who provide tour services strictly as an incidental part of their cab operations are exempted from the certificate rule.