Trump administration officials took steps on Friday to crack down on transparency at one of the largest US federal agencies, proposing a slew of changes that could make it harder for the public and media to obtain records of agency dealings.

The proposal is part of an effort to grapple with what the interior department describes as an “unprecedented surge” in requests under the Freedom of Information Act (Foia), the United States’ pre-eminent open government law, since 2016 when Donald Trump took office.

Among other wide-ranging revisions to its Foia regulations, the interior department’s proposal would enable the agency to reject Foia requests that it considers “unreasonably burdensome” or too large, and it would allow the agency to impose limits on the amount of records it processes for individual requesters each month.

The department oversees hundreds of millions of acres of public land, including national parks, as well as the country’s endangered species programs. Under the Trump administration, the department has embarked on an aggressive agenda of opening these lands to oil and gas drilling and mining while rolling back a wide variety of environmental regulations.

Records uncovered using the Freedom of Information Act in recent months have revealed the department’s close ties with energy industry groups as well as several apparent ethics violations among top political officials.

Daniel Jorjani, one of interior’s top lawyers and a former employee of the Koch-brother-backed conservative group Freedom Partners, signed off on the proposed revisions, which are facing harsh criticism from civil society groups that rely on Foia to track the department’s actions.

“This is a war on transparency,” said Jeremy Nichols, the climate and energy program director at WildEarth Guardians, an environmental group that regularly files Foia requests and which first flagged the interior department’s proposal. “This is a calculated attempt to shield the interior department from scrutiny, to shield it from watchdogs, and to shield it from accountability.” Nichols said his organization would challenge the revised regulations in court if the need arose.

Interior department spokesperson Heather Swift declined to answer questions concerning the proposed changes, writing in a statement that “the department is unable to respond to media inquiries that are unrelated to the lapse in appropriations”.

The interior department oversees hundreds of millions of acres of public land, including national parks. Photograph: Robyn Beck/AFP/Getty Images

The changes are part of a broader drive to limit public access to interior department records. In October, the Guardian reported on a leaked interior department guidance that directed US Fish and Wildlife Service employees around the country to take a less transparent approach when responding to Foia requests about the agency’s endangered species programs.

During the week of the Thanksgiving holiday, meanwhile, the outgoing interior secretary, Ryan Zinke, tapped Jorjani to oversee the department’s Foia program, elevating a political appointee to a role normally reserved for career staffers.

Jeff Ruch, the executive director of Public Employees for Environmental Responsibility, a government transparency group that is one of the top Foia litigators in the country, said the interior department’s proposed revisions do contain a few positive changes. For instance, although they would give the agency more leeway to deny certain parties, including some members of the press, fee waivers under the law, they extend the period to appeal a denied fee waiver from 30 to 90 days.

Overall, though, Ruch said the department’s efforts to alter its Foia policies will “increase the burden on requestors and create a lot more confusion”.

“This appears to be an attempt to buttress the bunker and make the department less transparent,” he says.

The public has until 28 January to comment on the proposed revisions.