DETROIT >> Billionaire entrepreneur Elon Musk says he has “verbal government approval” to build a tunnel for high-speed transportation from New York to Washington that could break ground by the end of this year.

Musk didn’t say who gave him the approval, and he acknowledged that the deal is far from finalized.

But the White House confirmed it had “positive discussions” about the tunnel with Musk and executives from his underground drilling enterprise, The Boring Co. A White House spokesman wouldn’t say who talked to Musk or whether he met with officials in person.

“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,” the White House said in a statement.

In its own statement, The Boring Co. said feedback on the proposal has been positive and it has “received verbal support from key government decision-makers for tunneling plans.” The company said it expects to secure the formal approvals necessary to break ground later this year.

Musk runs electric car company Tesla Inc. and rocket maker Space Exploration Technologies Corp., among other ventures. He is also a backer of so-called hyperloop systems, which move pods at high speeds through vacuum-sealed tubes.

Musk said hyperloop tunnels could ferry people, cars and even bikes from New York to Washington in 29 minutes. That trip currently takes a little under three hours on Amtrak’s high-speed Acela Express. The system would also have stops in Philadelphia and Baltimore, Musk said.

In a later tweet, Musk said his priority with The Boring Co. is building tunnels to alleviate Los Angeles traffic. After that, he’s like to build one hyperloop system on the East Coast and one from Los Angeles to San Francisco. He said Chicago has also talked to the company about building a high-speed tunnel to O’Hare International Airport.

Musk said a lot of work needs to be done to get final approval, but he said he’s “optimistic that will occur rapidly.” He urged supporters to contact their representatives to speed that process.

But some cast doubt on his timeline, pointing out that Musk would have to get approval from dozens of players, including federal, state and local officials.

“This is news to City Hall,” tweeted Eric Phillips, a spokesman for New York City Mayor Bill de Blasio, in response to Musk’s tweets.

Mike Dunn, a spokesman for the city of Philadelphia, said Musk also has not contacted officials there.

“There are numerous hurdles for this unproven hyperloop technology before it can become reality,” Dunn said.

At the very least, the tweets showed Musk is still engaging with the White House. President Donald Trump named Musk to White House councils on business and manufacturing earlier this year. But Musk quit both councils last month after Trump announced he would withdraw the U.S. from the Paris climate accords.