WASHINGTON (REUTERS) - A US congressional panel is investigating Environmental Protection Agency Administrator Scott Pruitt's use of a condominium tied to an energy lobbyist, a House Republican aide said on Saturday (April 7).

The House of Representatives Oversight Committee, chaired by Republican Representative Trey Gowdy, has begun looking into Pruitt's housing arrangements, according to the aide, who was not authorised to speak publicly.

The EPA had no immediate comment.

The panel's probe adds to the pressure on Pruitt, a vocal critic of mainstream climate change science who sued the EPA more than a dozen times when he was Oklahoma's attorney-general.

Many Democrats and even a few Republicans have said should resign or be fired.

Lawmakers have been scrutinising Pruitt for renting a room in a high-end townhouse co-owned by the wife of energy industry lobbyist Steven Hart for US$50 (S$65) a night, an arrangement that has drawn fire from ethics experts. Media reports say the payment is less than one-third the price of similar properties.

Hart lobbies for companies regulated by the EPA.

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Pruitt is also under fire for frequent first-class air travel and for purchasing costly items for his office, including a soundproof telephone booth.

"I don't have a lot of patience with that kind of stuff,"Gowdy said of Pruitt in a video released by the environmental group Friends of the Earth. "You've just got to be a good steward of public services."

As part of the committee's investigation, the EPA has produced documents, including a memo from the EPA ethics office that initially cleared Pruitt of accepting a gift from a lobbyist but did not address whether he broke other federal ethics regulations.

An administration official said Pruitt met with President Donald Trump on Friday morning, a week after White House Chief of Staff John Kelly advocated for Trump to fire him.

Trump told reporters on Thursday that he would take a look into ethics allegations against Pruitt but added the official was doing a"fantastic job."