Energy Secretary Jennifer Granholm earlier this week chartered a military jet to attend a diplomatic summit in Ukraine as the Pentagon struggled to evacuate Americans and allies from Afghanistan with limited time and operational resources, sources told the Washington Free Beacon.

Granholm's flight took place amid the United States' frantic effort to airlift tens of thousands of people from Afghanistan ahead of the Taliban's Aug. 31 deadline, and as the Department of Defense was forced to call in civilian airlines to bolster its strained evacuation fleet.

The secretary's use of a military jet — and particularly the flight's timing — may raise questions for the Biden White House, which is responsible for approving such flights. Trump administration officials faced allegations of wasteful spending for their use of expensive military charters for trips that did not have national security urgency.

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Tom Price, who served as Health and Human Services secretary under former president Donald Trump, was forced to resign in 2017 amid revelations that he took numerous overseas military flights and other private air travel, running up a $500,000 travel tab. Trump's former Environmental Protection Agency administrator Scott Pruitt resigned in 2018 amid multiple controversies, including questions over his use of military flights that cost the government over $58,000. Former Treasury Secretary Steven Mnuchin was also scrutinized for taking military flights for unnecessary purposes.

"As President Biden recently said, we are in a ‘winter of peril,' so it’s disconcerting to see administration officials essentially taking joy rides on military aircraft.  It's the definition of fraud, waste, and abuse," said Tom Anderson, director of the National Legal and Policy Center's Public Integrity Project.

The White House confirmed to the Free Beacon that Granholm used a military flight and defended it as "standard protocol" because Granholm was attending the event as a dignitary, representing the president.

Others questioned the justification. 

"Standard operating procedure does not apply during a national security crisis; these moments require judgment," one former Trump administration official told the Free Beacon. "The fact that the White House chose to send a cabinet member overseas on a non-mission-essential visit, unnecessarily diverting State Department and DOD resources, is ludicrous, not to mention an abuse of taxpayer dollars."

The official added that the military charters "require refueling and the support of personnel at military bases such as Ramstein Air Base, which is currently being used to transport and house thousands of people fleeing Afghanistan."

The Department of Energy declined to comment on the justification for the flight and how much it cost.

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Granholm on Monday flew to Ukraine to attend the Crimea Platform Summit, a conference to support Crimea's independence from Russia.

Also on Monday, the Pentagon instituted an emergency program called the "Civil Reserve Air Fleet," which ordered civilian airlines, including American Airlines and Delta Airlines, to provide planes to help the evacuation efforts from Afghanistan. The program was last used during the early days of the Iraq war.

"It's a program that was designed in the wake of the Berlin airlift after World War II to use commercial aircraft to augment our airlift capacity," President Biden said earlier.

Click here to read more on the Washington Free Beacon.