In a tantalizing Tweet, Elon Musk says he has "verbal government approval" to build a tunnel for high-speed transportation from New York to Washington.

The billionaire entrepreneur didn't say who gave him the approval.

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.

Musk says the tunnel could ferry people and cars from New York to Washington in 29 minutes. The system would also have stops in Philadelphia and Baltimore.

In a follow-up Tweet, Musk urged Americans eager for the hyperloop to get in contact with their local lawmakers.

Musk initially served on two White House business councils, but quit them last month after President Donald Trump announced he would withdraw the U.S. from the Paris climate accords.

The Boring Company released this statement Thursday evening clarifying Musk's tweet:

"The Boring Company has had a number of promising conversations with local, state and federal government officials. With a few exceptions, feedback has been very positive and we have received verbal support from key government decision-makers for tunneling plans, including a Hyperloop route from New York to Washington DC. We look forward to future conversations with the cities and states along this route and we expect to secure the formal approvals necessary to break ground later this year."

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