MINNEAPOLIS (AP) - A German-operated cargo ship and crew have been stuck at anchor outside the Lake Superior port of Duluth for close to a month for unspecified environmental violations. And there's no resolution in sight despite the upcoming closure of the St. Lawrence Seaway for the winter.

The U.S. Coast Guard says the Liberian-flagged Cornelia is being investigated for "alleged violations of U.S. environmental regulations." And it says the ship and crew are prohibited from leaving Duluth until they get clearance.

The Coast Guard won't say what the violations were, though it says they didn't take place in Duluth.

Duluth Seaway Port Authority spokeswoman Adele Yorde says such detentions don't happen very often, perhaps once or twice a year across the Great Lakes system, and don't usually take so long to resolve.