Republican presidential candidate Donald Trump is considering nominating Oklahoma oil and gas mogul Harold Hamm as energy secretary if elected to the White House on Nov. 8, according to four sources close to Trump's campaign.

The chief executive of Continental Resources would be the first U.S. energy secretary drawn directly from the oil and gas industry since the cabinet position was created in 1977, a move that would jolt environmental advocates but bolster Trump's pro-drilling energy platform.

Dan Eberhart, an oil investor and Republican financier, said he had been told by officials in Trump's campaign that Hamm was "the leading contender" for the position.

Eberhart said he had discussed the possible appointment with top donors at the Republican National Convention in Cleveland this week.

Three other sources close to the Trump campaign confirmed Trump was considering Hamm for the post. One of the sources said he first heard that Hamm was a contender from Trump officials on Sunday.

Hamm, 70, became one of America's wealthiest men during the U.S. oil and gas drilling boom over the past decade, tapping into new hydraulic fracturing drilling technology to access vast deposits in North Dakota's shale fields.

Hamm's future was discussed at a private fundraiser organized by a Trump Super PAC, Great America PAC, in Cleveland on Monday. Hamm was there, along with major donor Foster Friess and former Republican presidential candidate Ben Carson, one of the sources said, asking not to be named.

None of the sources was aware of who else Trump may be considering for the job.