WASHINGTON, May 21 (UPI) -- While gasoline prices rise, the United States has an abundance of currently unavailable energy, the U.S. Bureau of Land Management said Wednesday.

"America has abundant energy resources," said C. Stephen Allred, assistant secretary of the Interior for Land and Minerals Management.

"However, for a variety of reasons, many of these resources are not available," Allred said.

A Bureau of Land Management report released Wednesday said public lands in the United States are estimated to contain 31 billion barrels of oil and 231 trillion cubic feet of natural gas.

Sixty percent of the federal lands sitting on energy supplies "are presently closed for leasing, making 62 percent of the oil and 41 percent of the natural gas inaccessible," a U.S. Department of the Interior release concerning the report said.

Additionally, the statement said, 30 percent of onshore federal oil reserves and 49 percent of the natural gas reserves are subject to various restrictions.

Only 8 percent of the oil reserves and 10 percent of the natural gas reserves are accessible "under standard lease terms," the statement said.