A federal agency that has jurisdiction over California's bullet train has ruled that it has the authority to pre-empt state environmental law, creating uncertainty for numerous groups fighting the project in court.

In a decision made public Monday, the U.S. Surface Transportation Board ruled that lawsuits challenging the high-speed rail line under the California Environmental Quality Act conflict with its authority over railroads.

The three-member board was acting on a request from the California High-Speed Rail Authority, which was seeking to clarify federal jurisdiction over the project.

The authority faces seven lawsuits that use the state environmental law to challenge the bullet train plans. Officials were concerned that the lawsuits could delay construction of one of the initial sections of track, a 114-mile line between Fresno and Bakersfield.

In its 2-1 decision issued late Friday, the federal body said the California environmental law "could be used to deny or significantly delay an entity's right to construct a line that the Board has specifically authorized, thus impinging on the Board's exclusive jurisdiction over rail transportation."

The ruling makes it clear that federal law has precedent over state law as it pertains to construction of the high-speed rail line, said Lisa Marie Alley, spokeswoman for the California High-Speed Rail Authority. She said agency officials were still reviewing the decision.

Yet it also has the potential to muddy the legal waters.

The dissenting member of the federal board, Ann D. Begeman, said the ruling removes key decision-making abilities from state residents, whose interests are at stake in the construction of the north-to-south rail line.

The ruling also conflicts with a previous decision by a California appeals court in a case involving several municipalities south of San Francisco that are challenging the project.

The California Court of Appeal previously decided in favor of Atherton, Menlo Park, Palo Alto and a collection of community groups, ruling that the California environmental law is not pre-empted by federal jurisdiction.

"Nobody's really quite sure what to do with this," said Stuart Flashman, an Oakland attorney representing the plaintiffs in the Atherton case.

He said the opposition groups could ask the Surface Transportation Board to reconsider its decision or appeal it in federal court.

Officials with Kings County, which is included in one of the state lawsuits against the bullet train project, were examining the board's ruling and trying to determine their next step.

"It practically invites more litigation," Colleen Carlson, the attorney for Kings County, said in an emailed statement.

Carlson said the ruling also disregards a provision of Proposition 1A, the voter initiative that authorized the project. That provision says the environmental work for the first 300 miles must be completed before any state bond money is spent.

The rail authority approved an extensive environmental impact report for the Fresno-to-Bakersfield section in May.