Pruitt has declined to comment on the rental arrangement reported last week and a spokesman for the agency on Friday defended his conduct and said the lease agreement was in line with federal ethical regulations.

The Journal quoted the official as saying the purpose of the inquiry was to “dig a little deeper.” Another White House official said few people were coming to Pruitt’s defense, the newspaper said, although there is no sign yet that his position is in jeopardy.

The White House did not immediately respond to a request for comment.

ABC News and Bloomberg News reported last week that during his first six months in Washington last year, Pruitt made a deal to pay about US$50 a night – less than a third the price of similar properties – to rent a room in a Capitol Hill neighborhood condo building co-owned by energy industry lobbyist Steven Hart and his wife.

Pruitt, a conservative who previously served as Oklahoma’s attorney general, is also one of several members of President Donald Trump’s Cabinet who have come under scrutiny for their travel practices.

The EPA confirmed last month that Pruitt’s private security detail accompanied him on first-class flights.

Hart’s firm represents companies regulated by the EPA including Oklahoma Gas & Electric Co, shale producer Concho Resources Inc, ExxonMobil Corp and liquefied natural gas (LNG) company Cheniere Energy Inc.

Travel records obtained through a public records request show that Pruitt spent over US$17,000 in taxpayer money for a December trip to Morocco to promote US exports of LNG. Marketing US LNG is not the jurisdiction of the EPA administrator.