Chinese and Russian business executives with ties to their governments have been secretly discussing plans for an underwater tunnel to connect Russia with Crimea and creating a hidden transportation route to protect it from Ukrainian attack, according to communications that Ukraine's security services say they've intercepted.

The talks, including some in late October, started because of Russian concern about a Kerch Strait bridge used by the Russian military after the Ukrainian military bombed the structure twice, reports The Washington Post.

U.S. officials and engineering officials say constructing a tunnel near the bridge would be largely difficult and would cost billions of dollars to build. Further, such work has never been attempted in an active war zone, they said.

Further, the project would cause risks for China both politically and financially, as it has never recognized the Russian annexation of Crimea officially. Further China could face economic sanctions from the United States and the European Union like the ones that have been put in place against Moscow.

But Alexander Gabuev, an expert on Moscow-Beijing relations at the Carnegie Russia Eurasia Center, said a tunnel could be vital for Russia, as it has not been able to wrap up the war with Ukraine, putting the Kerch bridge in danger of attack for many more years.

But even with the risks China could face, intercepted emails provided to the Post by Ukrainian officials show that one of the largest construction companies in China has signaled willingness to participate in the tunnel project.

The messages have been corroborated by other information the publication obtained including corporate registration files showing a Russian-Chinese consortium that involves people named in the emails has been formed in Crimea.

Other emails mention meetings with Chinese delegates in Crimea, including one that was dated Oct. 4 saying the Chinese Railway Construction Corporation, CRCC, is "ready to ensure the construction of railway and road construction projects of any complexity in the Crimean region."

CRCC is a state-owned company that built many of China's largest road and rail networks and has worked in Russia, including on an extension of the Moscow subway system completed in 2021.

Vladimir Kalyuzhny, a Russian businessman identified in documents as the general director of the consortium examining a tunnel, meanwhile, said the news is a "lot of hot air" and ended a call for comment by refusing to provide information to the "enemy media."

But Kalyuzhny said in a message sent last month to Georgiy Muradov, a Russian official and one of Crimea's main representatives in Moscow that he got a letter "from our Chinese partners about the readiness of one of the largest companies in China, CRCC, to participate as a general contractor in the construction of a tunnel under the Kerch Strait."

The proposal for a tunnel comes while Russia is pushing for other infrastructure projects in territories occupied since or those seized after the invasion of Ukraine.

The emails also show China attempting to keep the talks quiet, with one emphasizing the CRCC will participate will take part in the project only if there is "complete confidentiality" including replacing its name on documents with another unaffiliated legal entity.

Yet another email says China is willing to "Another email mentions a Chinese bank willing to "convert its dollar funds into rubles for their transfer to Crimea to fund [consortium] projects."

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