BILLINGS, Mont. (AP) — A U.S. senator said Tuesday he will ask fellow lawmakers to halt coal sales on federal lands in the West after a senior Obama administration official declined to suspend the troubled government program.

Massachusetts Sen. Ed Markey said the Interior Department moved too slowly on promised reforms since the Democrat raised concerns earlier this year that “bargain-basement” lease sales to a handful of mining companies might have cost taxpayers $200 million or more.