JUNEAU, Alaska - President Barack Obama is proposing to designate the vast majority of Alaska's Arctic National Wildlife Refuge as a wilderness area, including its potentially oil-rich coastal plain, drawing an angry response from top state elected officials who see it as a land grab by the federal government.

"They've decided that today was the day that they were going to declare war on Alaska. Well, we are ready to engage," said U.S. Sen. Lisa Murkowski, R-Alaska, and chair of the Senate energy committee.

The designation would set aside an additional 12.2 million acres as wilderness, including the coastal plain on Alaska's northeast corner, giving it the highest degree of federal protection available to public lands. More than 7 million acres of the refuge currently are managed as wilderness.

The refuge's coastal plain has long been at the center of the struggle between conservationists and advocates of greater energy exploration in the U.S. Political leaders in Alaska have supported allowing for exploration and production within the coastal plain. They have opposed attempts to further restrict development on federal lands, which comprise about two-thirds of the state, including within the National Petroleum Reserve-Alaska.

A resolution passed the state Legislature with bipartisan support last year urging Congress to allow for exploration and development on the coastal plain. A federal lawsuit brought by the state over the Interior Department's refusal to consider a proposed exploration plan for the refuge's coastal plain is pending. The state in 2013 proposed an exploration plan that it said was aimed at determining the true oil and gas potential in the refuge.

The Republican congressional delegation, along with Alaska's new governor, Bill Walker, sent out a joint news release Sunday morning calling the action "an unprecedented assault on Alaska." Walker changed his GOP affiliation to undeclared in running for office last year.

In a White House video released Sunday, Obama said he is seeking the designation "so we can make sure that this amazing wonder is preserved for future generations."

The Interior Department issued a comprehensive plan Sunday that for the first time recommended the additional protections. If Congress agrees, it would be the largest wilderness designation since passage of the Wilderness Act in the 1960s, the agency said.

However, the proposal is likely to face stiff resistance in the Republican-controlled Congress. Murkowski said in an interview that Obama is going after something "that is not possible in this Congress." She said she sees it as an attempt by the administration to "score some environmental points" and to rile passions ahead of another announcement by Interior in the coming days that Murkowski said she was told would propose putting off-limits to development certain areas of the offshore Arctic.

Murkowski said she spoke with Interior Secretary Sally Jewell and Jewell's chief of staff in the last few days.

An Interior Department spokeswoman, responding by email Sunday, did not offer details but said a proposed five-year offshore drilling plan is forthcoming and that environmental reviews of lease areas in the Arctic waters off Alaska's shores are underway.

The department pegged the timing of Obama's announcement in part to recent legislation proposed in Congress and talks involving potentially opening the refuge to development. Earlier this month, U.S. Rep. Don Young, R-Alaska, introduced a bill that would allow for development on the coastal plain. On Wednesday, in his first State of the State speech, Walker talked about working with the congressional delegation to tap the oil within the refuge. Murkowski referenced the refuge - and the economic benefits that she said could come from tapping a part of the refuge - in an energy-focused Republican weekly address on Saturday.

Murkowski, who also chairs the Interior appropriations subcommittee, said Sunday that the days of Obama administration officials knowing they can call her and get a call back are done.

Young, in a statement, called the proposed wilderness delegation a violation of the Alaska National Interest Lands Conservation Act. "Simply put, this wholesale land grab, this widespread attack on our people and our way of life, is disgusting," he said.

Conservation groups hailed Obama's announcement.

David Houghton, president of the National Wildlife Refuge Association, said in a statement released by conservation and some Native organizations that the refuge's coastal plain "is one of the last places on earth that has been undisturbed by humans, and we owe it to our children and their children to permanently protect this invaluable resource."

Robert Thompson, who lives within the refuge's borders at Kaktovik and is chairman of the group Resisting Environmental Destruction on Indigenous Lands, worries that oil and gas development would displace Native subsistence activities. He said he was pleased with Obama's action, even if it is symbolic.