WASHINGTON, April 3 (Reuters) - The Obama administration on Friday finalized its recommendation to expand protected areas of Alaska's Arctic National Wildlife Refuge, calling on Congress to block about 12 million acres (5 million hectares) from oil and gas drilling.
U.S. President Barack Obama, in a letter to House Speaker John Boehner released by the White House, stood by his administration's earlier recommendation to preserve a wide swath of the state's Arctic refuge, setting up a likely battle with the Republican-led Congress over the oil-rich area.
"This area is one of the most beautiful, undisturbed places in the world. It is a national treasure and should be permanently protected through legislation for future generations," Obama said in the letter.
The Interior Department first released its proposal calling for the expanded protections in January but faced instant rebuke from Republicans, who are pushing energy issues such as the refuge and the Keystone XL pipeline as a major part of their economic platform ahead of the 2016 elections.
In his letter to Boehner on Friday, Obama said the department had since reviewed available science and public comments in making its final recommendation. He called on Congress to authorize the expansion, a move likely to face fierce resistance in Congress.
The additional 12 million acres would include the refuge's Coastal Plain. In addition to the current off-limits area, it would bring the refuge's total protected wilderness area to nearly 20 million acres (8 million hectares).
At the same time, the Obama administration is close to approving Arctic drilling for Royal Dutch Shell for the first time since the company's mishap-plagued 2012 drilling season.
Environmentalists have hailed the proposed designation, the highest level of federal protection under which oil and gas drilling is banned, while Republicans have long-called for opening up the area to boost domestic energy production.
Republican Lisa Murkowski of Alaska, the head of the Senate Energy and Natural Resources Committee who has introduced legislation permitting oil production in the Arctic refuge, blasted the move, vowing to block it.
"We will continue to fight against the administration's efforts to impose new restrictions on Alaska's lands and resources," she said. "A congressional designation of the Coastal Plain as wilderness will not happen on my watch."
More than 15 environmental advocacy groups, including the Sierra Club and the League of Conservation Voters, vowed their support in a joint statement.
"We're pleased to see President Obama courageously follow through on his commitment to protect the coastal plain of the Arctic National Wildlife Refuge," said Defenders of Wildlife President and Chief Executive Officer Jamie Rappaport Clark. (Additiona reporting by Timothy Gardner; Editing by Sandra Maler)