Trump overwhelmingly won the state in the November election, partly due to his promises to revive a slumping coal industry.

At a boisterous campaign rally in Trump-friendly West Virginia, US President Donald Trump slammed the investigation as a “fake story that is demeaning to all of us and most of all demeaning to our country and demeaning to our Constitution.” He commented hours after news broke that Robert Mueller, the special counsel leading the investigation, had empaneled a grand jury in the case.

“I just hope the final determination is a truly honest one, which is what the millions of people who gave us our big win in November deserve and what all Americans who want a better future want and deserve,” Mr. Trump told thousands of cheering, sign-waving supporters packed into an arena in Huntington.

Mr. Trump overwhelmingly won the state in the November election, partly due to his promises to revive a slumping coal industry.

The president, who remains agitated over the investigation into allegations of coordination between his campaign associates and Russian government officials, said Democrats have a decision to make.

“They can continue their obsession with the hoax or they can serve the interests of the American people,” he said.

Mr. Trump maintains there were no ties between his campaign and Russia and says no wrongdoing was committed. His frustration over the investigation peaked in recent weeks as he began attacking Attorney General Jeff Sessions for recusing himself from the investigation. Sessions, most recently a U.S. senator, was an early and ardent Trump supporter.

“Most people know there were no Russians in our campaign. There never were,” he told the cheering crowd in West Virginia. “We didn’t win because of Russia. We won because of you.”

Mr. Trump argued that Democrats are pushing the “totally made-up Russia story” because “they have no message, no agenda and no vision.”

“The Russia story is a total fabrication. It’s just an excuse for the greatest loss in the history of American politics,” he said, referring to his victory over Hillary Clinton. “It just makes them feel better when they have nothing else to talk about.”