Tech entrepreneur Elon Musk on Thursday said he had received "verbal" approval to start building a high-speed underground transport system linking New York and Washington that could cut travel time between the cities to about half an hour.

Musk, the chief executive of electric car maker Tesla Inc. and rocket company SpaceX, is seeking to revolutionize transportation by sending passengers and cargo packed into pods through an intercity system of giant vacuum tubes known as the "hyperloop."

He recently started a project, the Boring Company, to build transport tunnels for the system, which he says would be far faster than current high-speed trains and use electromagnetic propulsion.