JUNEAU -- The state of Alaska is suing to block the federal government from enforcing regulations for emissions from cruise ships and marine cargo carriers.

New rules taking effect Aug. 1 would require that freight lines and cruise ships off the Southeast and southern coasts of Alaska use low-sulfur fuel. The state says the fuel is expensive and difficult to obtain. It also says the new regulations will greatly increase shipping costs to Alaska and hurt the state's tourism sector.

The state, in its lawsuit, claims the U.S. Environmental Protection Agency lacks the legal authority and scientific basis to extend what's known as an Emission Control Area to Alaska.

It says enforcement will "irreparably injure the State and Alaska's citizens and economy."

An EPA spokeswoman couldn't immediately comment on the lawsuit.