Washington (CNN) Multiple senior officials at the Environmental Protection Agency were sidelined or demoted after they pushed back on or raised concerns about Administrator Scott Pruitt's pricey travel, office spending and management of the agency, two sources with direct knowledge of the matter told CNN.

Pruitt's international travel, frequent trips to his home state of Oklahoma and exorbitant office expenditures have drawn concerns from ethics experts and yielded headlines for months, but two sources familiar with the matter said they could have been avoided had Pruitt heeded the advice of multiple EPA officials -- both career officials and political appointees. Instead, the sources said, the officials who disagreed with Pruitt were iced out, reassigned or demoted.

Kevin Chmielewski, who was one of the longest-serving top advance officials on President Donald Trump's campaign, was stripped of his work phone and ID card and placed on administrative leave, two sources with direct knowledge of the matter said. He had previously served as a deputy chief of staff for operations.

Two career officials were also pushed aside, a source with direct knowledge of the matter said. John Reeder was moved to American University as an "executive in residence" after clashing with Pruitt. His deputy who succeeded him as acting deputy chief of staff, Reginald Allen, was effectively demoted.

EPA spokesman Jahan Wilcox disputed the allegations and said in a statement: "This is a group of disgruntled employees who have either been dismissed or reassigned."

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