Sept 19 (Reuters) - The U.S. Justice Department said on

Friday that it filed a statement of interest last week in a case

between Enbridge Energy and the State of Michigan in the U.S.

District Court for the Western District of Michigan.

The department said its statement highlights that shutting

down Enbridge's ( ENB ) international pipeline interferes with the

United States' exclusive authority in foreign affairs.

"The federal government already comprehensively regulates

pipeline safety, but Michigan is trying to usurp the Department

of Transportation's statutory authority," said Adam Gustafson,

acting assistant attorney general of the Justice Department's

Environment and Natural Resources Division.