CHICAGO (AP) -- Gov. Pat Quinn says he's working "night and day" with other top Illinois leaders on ways to address the critically low water levels on the Mississippi River.

The river covers hundreds of miles of the state's border and is important to agriculture in Illinois, particularly because many of the state's products are transported on the river.

The nation's worst drought in decades has led to low levels. If they worsen, barge operators fear the waterway could become impassable.

Quinn said Thursday that he continues to work with U.S. Sen. Dick Durbin on solutions.

The weekly U.S. Drought Monitor on Thursday said the nation's drought has leveled off after worsening levels in the previous weeks. More than 62 percent of the contiguous U.S. remains in some form of drought.