In the next three years, Russia has planned to spend $3.6 billion (209 billion rubles) to boost economic growth. Most of those funds will be spent on building a nuclear icebreaker — a giant ship run on nuclear energy meant to smash through Arctic waters covered in ice.

The goal is to explore the region’s continental shelf, and in the process, find energy reserves of oil and natural gas, reported the Moscow Times Monday. The billions of dollars in funding will also go to helping indigenous communities, monitoring the environment and raising sunken nuclear vessels.

The announcement wasn’t the first nuclear icebreaker for Russia. Last June, the country launched the Arktika in St. Petersburg, a 567-foot, 33,500-ton ship that was able to smash through ice almost ten feet thick.

The news of Russia’s aggressive expeditions in the Arctic has worried some officials in the U.S., who’ve been concerned that the U.S. was missing an opportunity — and handing one to Russia — to find untapped energy potential in the northern seas. Tensions between Russia and the U.S. had already been mounting after U.S. intelligence agencies announced in December their conclusion that Russia had interfered with American elections. The race to find energy in the arctic has only unnerved some lawmakers even further.

One lawmaker, Rep. Duncan Hunter (R-Calif.), even wrote a letter to President Donald Trump regarding the matter last week. 

“Russia is launching its biggest icebreaker — The Arktika. It should be of tremendous concern that next to this vessel, there is no equivalent in the world,” he wrote. “In other words, Russia is not just exceeding the U.S. in icebreaker production and Arctic presence, they’re in a class by themselves and setting a standard, supported by enhanced capability, that is unmatched.”

Hunter then encouraged Trump to invest in building six more icebreakers for the Coast Guard, which currently only has two. Neither of them is nuclear-powered. In contrast, Russia already has 40 icebreakers; nine of those are powered by nuclear energy.

“We must act with the same sense of urgency,” Hunter added.