SEATTLE -- Metro Transit says special bus service to sporting events and community festivals may end because of new rules from the federal government.

In a news release issued Friday, Metro said the rules from the Federal Transit Administration may stop the transit agency from providing bus service to sporting events at Safeco Field, Qwest Field and Husky Stadium.

The FTA rules that went into effect April 30 are intended to open special event service to private charter companies, Metro said.

The rules mean that Metro won't offer its Pony Express Shuttle to Emerald Downs in Auburn beginning this weekend.

Metro said service for Mariners games will continue until June 30, but the future of Metro's special buses to Mariners games this summer is unknown.

"If Metro service for an event falls under the new definition of charter service, the agency must first contact private charter firms registered with the FTA to see if any are interested in providing the service. If any firms indicate they are interested, Metro will be precluded from providing the service and the private operators will be given the opportunity to negotiate with the event sponsor for the transportation service," the news release said.

"If no private company is willing and able to provide the transportation service, Metro may be able to continue its special service to the venue," according to the news release.