U.S. President Donald Trump's administration has asked the Environmental Protection Agency (EPA) to temporarily halt all contracts, grants and interagency agreements, pending a review, according to sources.

The White House sent a letter to the EPA's Office of Administration and Resources Management ordering the freeze on Jan. 23, an EPA staffer told Reuters. "Basically, no money moving anywhere until they can take a look," the staffer said, asking not to be named.

The EPA awards billions of dollars worth of grants and contracts every year to support programs around environmental testing, cleanups and research. It was unclear if the freeze would impact existing contracts, grants and agreements, or just future ones.

Myron Ebell, who headed Trump's EPA transition team until his inauguration last week, said he believed the move was related to Trump's executive order on Jan. 23 temporarily halting all government hiring outside the military.

"A freeze at EPA on some other things like grants and contracts appears to have happened," Ebell told Reuters in an email the morning of Jan. 24.

The freeze was first reported by ProPublica on Jan. 23 and Ebell said it was similar to what has happened during previous presidential transitions.

Trump has promised to slash U.S. environmental regulation as a way to promote oil drilling and mining. An administration official told Reuters the president would sign two executive actions on Jan. 24 to advance construction of the Keystone XL and Dakota Access pipelines in a sharp reversal from the Obama administration.

Trump's nominee to run the EPA, Oklahoma Attorney General Scott Pruitt, is awaiting Senate confirmation. Pruitt sued the EPA repeatedly as Oklahoma's top prosecutor.

Trump also has drawn heavily from the energy industry lobby and pro-drilling think tanks to build its landing team for the EPA, according to a list of the newly introduced 10-member team seen by Reuters on Jan. 23.

An EPA spokesman did not immediately respond to a request for comment.

In a separate Jan. 23 news article, Reuters said that the email containing the list of the 10-member team lists at least three former researchers from think tanks funded by the billionaire industrialist brothers Charles and David Koch, and at least one former lobbyist for the mining industry. Several members of the team have also publicly argued against U.S. efforts to combat climate change.

The team's makeup has reinforced expectations that Trump will follow through on his promise to slash U.S. environmental regulation as a way to promote drilling and mining.

The team, charged with preparing the agency for new leadership, replaces the initial EPA transition group picked by Trump after the November election but before his swearing-in, Reuters said in that article.

"We are looking forward to working with the career professionals at the EPA to make this transition work as well as possible, and to carry out the agency's mission to protect public health and the environment," according to the email. "While transitions are always hard, straightforward honest communication combined with respect for each other will make the process work much better."

Charles Munoz was named in the email as White House liaison on the new EPA team. He was a top organizer for Trump in Nevada during his campaign for the White House, and helped set up the state's chapter of Americans for Prosperity, a political advocacy group funded by the Kochs.

Another team member, David Schnare, is a lawyer and environmental scientist who spent 33 years as a staffer at the EPA. More recently, Schnare was legal counsel at The Energy & Environment Legal Institute, which has received funding from the Koch brothers-linked Donors Trust fund. The institute describes itself as seeking to correct "onerous federal and state governmental actions that negatively impact energy and the environment."

Schnare has also worked at the Center for Environmental Stewardship at the Thomas Jefferson Institute for Public Policy, which has been funded partially by the Charles Koch Foundation.

George Sugiyama, who was part of the initial EPA transition team, is also listed as part of the new team. He was chief counsel for Sen. Jim Inhofe, R.-Okla., a vocal climate change doubter. Before working for Inhofe, Sugiyama lobbied on behalf of the National Mining Association.

David Kreutzer is also staying on from the initial team. Kreutzer was a senior research fellow at the Heritage Foundation, a group funded by foundations controlled by Koch Industries and other energy firms. He has called Obama's efforts to combat climate change costly and unfair to certain industries, and has advocated for more Arctic drilling.

The new EPA team's communications director is Doug Ericksen, a current Washington state Senator who has served as Trump's deputy campaign director for that state. Ericksen has a degree in environmental science and serves as chair of the Washington State Senate's energy and environment committee. He opposes the climate policies of Washington state's Democratic Gov. Jay Inslee, including targets to reduce greenhouse-gas emissions.

Holly Greaves will oversee budget issues on the landing team. She was a senior audit manager at KPMG, and previously worked at Ernst & Young in the firm's advisory services position, Reuters said.

Other team members included Justin Schwab, the EPA team's legal adviser, who used to work at law firm Baker Hostetler.

Sen. Don Benton, R.-Wash., who ran a county environmental department, was also listed, along with Patrick Davis, a Republican political consultant, and Layne Bangerter, an Idaho rancher who worked with Sen. Mike Crapo, R.-Idaho, on wilderness management bills.