EXCLUSIVE: Sen. John Kennedy, the top Republican on the Energy and Water subcommittee on Appropriations, is putting pressure on the Biden administration to put a stop to the arbitrary seizures of U.S. oil supplies by the Mexican government.

In a letter sent to Energy Secretary Jennifer Granholm on Wednesday, the Louisiana Republican said White House inaction to "reopen American assets" would prompt him to block Brad Crabtree as assistant secretary for fossil energy and carbon management, along with several others up for top jobs at the Department of Energy.

Senator John Kennedy, R-LA, speaks in the Hart Senate Office Building on Capitol Hill on March 2, 2021 in Washington, D.C. as FBI Director Christopher Wray testifies before the Senate Judiciary Committee about the January 6 attack on the U.S. Capitol.

Senator John Kennedy, R-LA, speaks in the Hart Senate Office Building on Capitol Hill on March 2, 2021 in Washington, D.C. as FBI Director Christopher Wray testifies before the Senate Judiciary Committee about the January 6 attack on the U.S. Capitol. (Photo by Graeme Jennings-Pool/Getty Images)

REPUBLICANS DEMAND BIDEN GIVE 'TIMELY AND CLEAR RESPONSE' TO MEXICO ALLEGEDLY HARMING US ENERGY COMPANIES

"This is a developing situation that involves a major sense of urgency from the Biden administration," Kennedy wrote in a letter first obtained by Fox News. "It is vital to America’s economic, environmental and national security interests that these facilities, which are American-owned assets, are immediately allowed to reopen."

Kennedy’s threat follows reports that Mexican President Andres Manuel Lopez Obrador – also referred to as AMLO – has directed militarized police forces to bar access to fuel storage facilities privately owned by U.S. businesses, first reported the Wall Street Journal last month.

American companies like Texas-based Monterra Energy and California-based Sempra Energy are among those unable to gain access to their fuel supplies.

Andres Manuel Lopez Obrador, president of Mexico, poses during a state visit to Mexico at Palacio Nacional Oct. 21, 2019 in Mexico City, Mexico. 

Andres Manuel Lopez Obrador, president of Mexico, poses during a state visit to Mexico at Palacio Nacional Oct. 21, 2019 in Mexico City, Mexico.  (Photo by Hector Vivas/Getty Images)

HIGHER OIL, ENERGY PRICES ‘HERE TO STAY,’ ANALYST SAYS

"Despite the companies’ continued efforts to work with ALMO’s regulators, multiple facilities remain closed and under supervision of the militarized police force," Kennedy said.

The senator said he has further learned that regulators are also "harassing" American-owned renewable energy facilities.

"It is obvious what is going on here – AMLO’s shutting down all foreign competition for his state-owned company, Pemex, and so far he’s getting zero resistance from U.S. officials in the Biden administration," he added.

Lopez Obrador has reportedly pushed to have the state revert to a 1970’s policy and place all energy production under the control of the Mexican government, a move that could jeopardize the U.S, Mexico, Canada Agreement (USMCA). 

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President Biden listens while meeting virtually with Andres Manuel Lopez Obrador, Mexico's president, in the Roosevelt Room of the White House in Washington, D.C., March 1, 2021.  

President Biden listens while meeting virtually with Andres Manuel Lopez Obrador, Mexico's president, in the Roosevelt Room of the White House in Washington, D.C., March 1, 2021.   (Anna Moneymaker/The New York Times/Bloomberg via Getty Images)

The White House will host the North American Leaders’ Summit Thursday, the first time in five years leaders from the three nations will meet to promote trilateral trade and economic integration, an event Kennedy believes would be an opportunity for the administration to address U.S. energy qualms.  

"I implore you to begin aggressive engagement with the AMLO administration and urge the White House to immediately initiate a dialogue between our countries," he said. "I hope the Biden administration understands that American workers will feel the consequences of inaction."

Fox News could not immediately reach Granholm for comment. 

Adam Shaw contributed to this report.