President Obama traveled to Louisiana Sunday to assure coastal residents that the government is doing all it can to control the oil spill in the Gulf of Mexico — he had little good news to offer, though.

Obama flew over the marshes of Louisiana’s Plaquemines Parish, where rich oyster and shrimp beds are jeopardized by the spill.

Oil continues to flow out of control from a wellhead nearly a mile below the surface of the Gulf, and Obama warned it could keep flowing for a long time.

“I think the American people are aware, certainly the folks down in the Gulf are aware that we’re dealing with a massive and potentially unprecedented environmental disaster,” Obama said.

The president said crews are using the most advanced technology to try to stop the leak, but efforts to cap the well have so far been unsuccessful.