The acres were opened by BLM when it approved 3,288 exploration leases last year, up from 2,909 in 2000.

But preliminary numbers from the Minerals Management Service showed that even though more land was being opened to drilling, crude production on federal onshore lands fell to an estimated 98.6 million barrels last year, down from 109 million barrels in 2000.

Similarly, natural gas production dipped to 2.074 trillion cubic feet from 2.089 trillion cubic feet a year earlier. The Bureau of Land Management and Minerals Management Service are both part of the Department of Interior.

"The problem is the West and ANWR are not substitutes (for each other), and we don't have anything in the West even close to the oil resource potential of ANWR," said Ed Porter, research manager with the American Petroleum Institute, who estimated that more than two-thirds of the land controlled by the BLM in the Rocky Mountain region is off-limits or highly restricted.

"If you can lease (the land) but can't develop it, it doesn't do you much good," he added.

Porter said there are about four billion barrels of oil scattered throughout the Western United States, much less than the up to 16 billion barrels estimated by the Bush administration in the Arctic refuge.

Environmental groups have opposed drilling in the Arctic refuge, claiming that 95 percent of the 264 million acres (106 million hectares) controlled by BLM are already open to drilling and have yet to be explored by oil and gas companies.

"The vast majority of our public lands are open to drilling or exploration," said Peter Rafle, communications director for the Wilderness Society.

Bush has long maintained that the United States, which imports more than half of the 19.3 million barrels it uses each day, must reduce foreign oil imports by increasing drilling on federal lands.

"For the good of the national security of our country, we ought to encourage more exploration in an environmentally way on American soil," Bush said last Friday during a trip to Des Moines, Iowa.

Public lands were responsible for producing 11 percent of the United States' natural gas, 5 percent oil and 35 percent of its coal last year.

PERMIT "GOLDRUSH" OVERSHADOWED BY ENERGY BILL DEBATE

Democrats have pushed for legislation that promotes energy efficiency and conservation while leaving nature reserves such as ANWR untouched.

Lawmakers began debating the energy bill this week, with Republicans wanting to amend the measure to allowing drilling in ANWR.

Some green groups such as the National Resources Defense Council fear that wrangling between Republican and Democratic lawmakers over ANWR has drawn attention from "the gold rush" of drilling permits being issued.

"What is happening (in the West) is totally unprecedented," said Johanna Wall, director for the National Resources Defense Council.