The US administration announced Monday a 20-year ban on new mining projects around the Grand Canyon, protecting the prized tourist area from the impact of uranium extraction for a generation.

Interior Secretary Ken Salazar said the ban would "protect the iconic Grand Canyon and its vital watershed from the potential adverse effects of additional uranium and other hard rock mining on over one million acres," or 400,000 hectares.

The move "is the right approach for this priceless American landscape," Salazar said, countering claims from Arizona Republicans who want to open up the land to new mining claims.

"People from all over the country and around the world come to visit the Grand Canyon," said Salazar. "Numerous American Indian tribes regard this magnificent icon as a sacred place and millions of people in the Colorado River Basin depend on the river for drinking water, irrigation, industrial and environmental use.

"We have been entrusted to care for and protect our precious environmental and cultural resources, and we have chosen a responsible path that makes sense for this and future generations."

Jane Danowitz of the Pew Environmental Group said the announcement means "Americans can celebrate today that the Grand Canyon is protected for future generations to enjoy."

She also called for reform of "the nation's antiquated mining law," which she said gives the industry "unfettered access to the majority of public lands in the west."

Sierra Club executive director Michael Brune also hailed the decision, saying, "The majesty of the Grand Canyon has inspired generations of Americans. It has and will continue to play a key role in our country's history, our culture and our economy. It is no place for destructive mining."

Salazar imposed a two-year moratorium on new mining around the Grand Canyon in 2009 to give his department time to study a long-term ban. In June, he extended the moratorium for an additional six months.

The ban does not prohibit previously approved uranium mining, and new projects that could be approved on claims and sites with valid existing rights, the agency said.

Other types of mineral extraction and geothermal energy could be done in the area, the agency said.

National Mining Association president Hal Quinn criticized the ban, saying it "is not supported by the findings of (the department's) own impact analysis, which provided no evidence to justify a massive withdrawal of land outside the Grand Canyon National Park."

A number of Republican lawmakers from the region have also opposed the ban.

Senator John McCain said in a statement the move "is a devastating blow to job creation in northern Arizona."

McCain argued that the ban would undermine a compromise on wilderness protection hammered out in the 1980s.

He said the decision "is fueled by an emotional public relations campaign pitting the public's love for the Grand Canyon against a modern form of low-impact mining that occurs many miles from the Canyon walls and in no way impacts the quality of drinking water from the Colorado River."

McCain and other lawmakers from Arizona and Utah sent a letter last year to Salazar claiming any new ban would create a "de facto wilderness" zone in a region that "conservationists previously agreed would remain accessible to the mining industry."

McCain's group has introduced a bill to enshrine what he called a "historic agreement" in 1984 "that designated parts of the Arizona Strip as wilderness and restored other lands to reasonable and safe uranium mining uses."