President Donald Trump said Friday that a Russian proposal for Elon Musk and his tunneling business, the Boring Company, to build an undersea rail tunnel through the Bering Strait was "interesting" and he'd have to think about it. "That's an interesting one," Trump said when asked about the suggested tunnel from Russia to Alaska. "We'll have to think about that. I hadn't heard that." Ukrainian President Volodymyr Zelenskyy said he was "not happy" with the idea following Trump's response. Kirill Dmitriev, an investment envoy for Russian President Vladimir Putin, suggested in posts on Musk's social media platform X that the project would be partly funded by Moscow. Dmitriev said it would be "a 70-mile link symbolizing unity." A tunnel like this would traditionally cost an estimated $65 billion to build, said Dmitriev, who is head of Russia's sovereign wealth fund, adding that The Boring Company and its technology could potentially reduce those costs to $8 billion and complete the project within eight years. "Let's build a future together!" he wrote.