A top Russian official is promoting the construction of a “Putin-Trump” rail tunnel under the Bering Strait to connect Russia and the United States, an idea that President Trump called “interesting.”

An investment envoy for President Vladimir Putin of Russia, Kirill Dmitriev, said the proposal calls for a 70-mile rail and cargo tunnel connecting Siberia to Alaska to be built by Elon Musk’s Boring Company.

Mr. Dmitriev, who also serves as head of the Russian Direct Investment Fund, estimated the project could be completed in eight years at a projected cost of less than $8 billion, far below previous estimates of more $65 billion by using The Boring Company’s advanced tunneling technology. He said the project would be funded by Moscow and “international partners.”

In a post on the social media platform X, Mr. Dmitriev pitched the idea directly to Mr. Musk. “Imagine connecting the U.S. and Russia — the Americas and Afro-Eurasia — with the Putin-Trump Tunnel, a 70-mile link symbolizing unity,” he wrote. “Let’s build a future together.”

The concept of a U.S.-Russia connection is not new. “The dream of a U.S.-Russia link via the Bering Strait reflects an enduring vision — from the 1904 Siberia-Alaska railway to Russia’s 2007 plan,” Mr. Dmitriev wrote. “RDIF has studied existing proposals, including the U.S.-Canada-Russia-China railroad, and will support the most viable.”

The proposal surfaced following a phone call between Mr. Trump and Mr. Putin, in which the two leaders agreed to meet in Budapest to discuss a potential resolution to the war in Ukraine.

When asked about the tunnel proposal on Friday, Mr. Trump expressed curiosity. “That’s an interesting one,” he said. “We’ll have to think about that. I hadn’t heard that.”

Mr. Trump also confirmed that Secretary of State Marco Rubio and other high-level advisers will meet with a Russian delegation before he sits down with Mr. Putin in Hungary.

The summit announcement appears to have blindsided President Volodymyr Zelensky of Ukraine, who was at the White House on Friday hoping to secure a commitment from Mr. Trump to provide his military with Tomahawk long-range missiles. That now appears less likely, at least before the meeting in Budapest.

Asked about the proposed Bering Strait tunnel, Mr. Zelensky said, “I’m not happy with this idea.” 

Any attempt to tunnel under the Bering Strait faces significant practical hurdles. The region is characterized by below-freezing temperatures, a lack of existing infrastructure, and frequent, deep earthquakes. The Boring Company has no experience operating in such harsh conditions, having worked until now in hot, dry areas with ample infrastructure.

The company has also faced regulatory scrutiny. ProPublica reported that The Boring Company was recently fined in Nevada for an “extraordinary number of violations,” including digging without approval and improperly handling waste. It is currently developing the “Music City Loop,” a 10-mile tunnel project in Nashville, which has drawn protests from residents over a lack of planning in the flood-prone city.

Mr. Musk’s business ties with Russia are also notable. His electric vehicle company, Tesla, has purchased millions of dollars worth of aluminum from Rusal, a firm founded by sanctioned Russian oligarch Oleg Deripaska. 

The Wall Street Journal reported in October 2024 that Mr. Musk held secret talks with Mr. Putin in 2022. During one conversation, Mr. Putin allegedly pressured Mr. Musk to withhold SpaceX’s Starlink satellite service from Taiwan as a favor to President Xi Jinping of China, a key ally of the Kremlin.