Environmental Protection Agency chief Scott Pruitt faces a make-or-break moment on Thursday, when he’s slated for a pair of congressional hearings, but he’ll be heading to the Hill without the full backing of the Trump White House.

Two sources familiar with Pruitt’s preparation for the hearing say that the EPA has turned down an offer from the White House to help prepare the administrator for what is sure to be a bruising few hours of questions about the ethics and government spending controversies that have dogged him of late.

One of the sources, a White House official, characterized the EPA’s response to the West Wing as “get lost.”

The White House and the EPA declined to comment.

The agency’s rebuke of the West Wing’s offer is just the latest episode in an increasingly tense relationship between Pruitt, once one of Trump’s preferred federal officials, and a White House senior staff that has increasingly distanced itself from the embattled EPA leader of late.

A Bloomberg story on Monday, which reported that the White House was discouraging allies from publicly defending Pruitt, further exacerbated those tensions, according to one source familiar with the dispute. EPA officials privately questioned the wisdom of putting Pruitt’s fate in the hands of presidential aides who are apparently less than committed to his political survival.

That view cemented on Tuesday with the leak of internal White House discussions that questioned whether Pruitt should remain in his post.

The lack of White House input on Pruitt’s upcoming testimony will leave the administrator to fend for himself in what is expected to be a highly hostile environment. He is slated to testify before House Appropriations and Energy and Commerce panels, and will likely face questions about his expensive travel habits, his spending on internal security measures, and the months that he spent living in a Washington DC condo owned by the wife of a prominent energy lobbyist.

Pruitt has earned President Trump’s trust through his persistent advocacy of a conservative energy and environmental agenda, including the rollback of major Obama-era regulations. But EPA officials suspect that that goodwill does not extend to most of the president’s staff, who have struggled to deal with cascading scandals involving high-level Trump administration officials, resulting in the resignations of two cabinet members so far.

There has been a now months-long erosion of trust and cooperation between Pruitt’s EPA and the senior ranks of Trump’s West Wing. When White House officials requested travel records from the EPA as part of an internal probe into Pruitt’s penchant for first class flights, EPA declined to provide the records, instead handing them over to congressional investigators. The concern, sources told The Daily Beast at the time, was that damaging information about Trump cabinet officials has been known to leak from the West Wing.

Early this month, White House Chief of Staff John Kelly conveyed to Pruitt in a phone call that, though he had the full public confidence of President Trump for now, the flow of damning news stories needed to stop.

“[It] was not a friendly buck-up call at all,” one Trump administration official described the conversation.