The Trump administration on Monday said the entirety of Alaska's petroleum reserve, including the half that had previously been unavailable for leasing to oil companies, is on the table for discussion as an area of future development.

The Bureau of Land Management said Monday it will take public comments to gauge interest in potentially holding lease sales for all of the 23 million-acre National Petroleum Reserve in Alaska, the nation's largest petroleum reserve.

The announcement is a first step in a potential rollback of protections for the reserve under an administration that wants to open up federal lands to development. The reserve in northern Alaska, usually known by its old initials, NPR-A, is attracting increased interest from industry, after ConocoPhillips in January announced a large discovery there. The reserve is also near other large discoveries recently announced by Spanish oil company Repsol and Caelus Energy Alaska.

The 11 million acres that is currently unavailable for leasing won't be part of the agency's next lease sale, expected to take place this winter. But some of that land could eventually be made available for future sales, though such a decision won't happen easily, a federal lands official said Monday.

"A lot of revisiting and additional analysis" would have to take place before more tracts could be made available, said Rob Brumbaugh, section chief for oil and gas for BLM Alaska.

At this point, the agency is "just gathering information," he said.

In 2013, an agency activity plan identified about half the reserve as available for annual lease sales, and about half as unavailable for leasing. The land that is currently unavailable primarily surrounds Teshekpuk Lake, an important habitat for migratory birds and other animals, and in the southern section of the reserve.

The agency's statement was part of a public notice issued Monday and follows an order signed by Interior Secretary Ryan Zinke in May to develop a revised activity plan to jump-start production in the reserve.

"This is land that was set up with the sole intention of oil and gas production; however, years of politics over policy put roughly half of the NPR-A off-limits," Zinke said upon signing the order in Alaska. "Using this land for its original intent will create good paying jobs and revenue" in Alaska and strengthen national security, he said.

A date has not been set for the agency's next lease sale for the reserve. About 10 million unleased acres has been identified as available for comment and nomination at the next lease sale.

The comments must be received by Sept. 7.

Oil companies are leasing 1.4 million acres in the reserve, mostly in the eastern section southeast of Utqiaġvik, formerly known as Barrow.