JUNEAU (AP) — The U.S. Environmental Protection Agency on May 25 proposed restrictions that would block plans for a multibillion-dollar copper and gold mine in Alaska’s salmon-rich Bristol Bay region, the latest in a long-running dispute over efforts by developers to advance the mine.

Critics of the Pebble Mine project called the move an important step in a years-long fight to stop the mine. But John Shively, the CEO of the Pebble Limited Partnership, which is pursuing the mine, called the EPA’s proposal a “political maneuver” and a preemptive effort to veto the project.

The EPA in a statement...