Local governments caught off guard by Elon Musk's Hyperloop announcement

— -- Local governments were apparently caught off guard by Elon Musk's announcement this morning that he has received "verbal" approval to bore a tunnel from New York to Washington, D.C., for a high-speed underground train he calls the Hyperloop.

"Just received verbal govt approval for The Boring Company to build an underground NY-Phil-Balt-DC Hyperloop," the billionaire tweeted this morning, boasting that the 200-mile trip would take just 29 minutes.

But the New York City mayor's office and spokespeople from the D.C. and Pennsylvania Departments of Transportation all told ABC News they were not aware of any ongoing projects involving Musk.

The U.S. Department of Transportation referred ABC News' inquiry to the White House.

“We have had promising conversations to date, are committed to transformative infrastructure projects, and believe our greatest solutions have often come from the ingenuity and drive of the private sector," a White House spokesperson told ABC News.

Musk, also the CEO of rocket manufacturer SpaceX and electric auto giant Tesla and a co-founder of PayPal, served on the administration's advisory council until Trump pulled out of the Paris climate accords.

His tunnel-digging operation, "The Boring Company" (pun intended), has already broken ground on an underground shaft near his rocket company in California to circumvent gridlock in Los Angeles.

"I find holes in the ground exciting," Musk quipped at an engineering competition in January. "We’ll see how far we can get, we’re just sort of muddling along."

The inimitable entrepreneur first revealed his design for the Hyperloop -- a travel pod designed to speed through an underground pneumatic tube at around 800 miles per hour -- in 2013.

After completing Hyperloop tunnels in Los Angeles and the Northeastern corridor, he plans to continue digging, with tunnels connecting Los Angeles to San Francisco and a network inside Texas, he suggested on Twitter.

"Still a lot of work needed to receive formal approval, but am optimistic that will occur rapidly," Musk clarified a few hours after posting his first tweet.