U.S. Senator Chris Murphy on Tuesday criticized Europe’s overreliance on Russian energy, saying it had come at a heavy cost and called on the region to start investing heavily in alternative supplies.

“What a mistake for Europe to have been welded to Russia when it comes to energy,” Democratic Party member Murphy told CNBC’s Hadley Gamble at the Warsaw Security Forum in Poland.

“We’re now seeing the price of that mistake, so let’s make up for lost time,” he said.

Europe has been at the forefront of the escalating global energy crisis borne out of Russia’s unprovoked invasion of Ukraine.

Once a major importer of Russian energy — previously relying on the country for up to 45% of its natural gas needs — the region is now faced with dwindling supplies and soaring prices as a result of its own sanctions against the Kremlin.

Time to spend

Murphy said the U.S. had made major steps forward in improving its energy security and urged Europe to follow suit.

“This is a moment for Europe to spend some money,” he said. “I know that’s hard to do when you’re right now dealing with such economic pressures. But this is the moment to spend money on nuclear energy, on renewable energy, on connecting to non-Russian pipelines.”

He hailed the U.S.’s Inflation Reduction Act, which was signed into law by President Joe Biden in August, and which includes a range of provisions to bolster the country’s transition toward clean energy.

Murphy said the measures would ensure the U.S. would no longer be dependent on “the Russians, nor the Saudis, or any other dictator” for future energy supplies.

He added that the U.S. may be willing to support Europe financially in its energy transition, saying it was in the interests of democratic nations.

“I’m hopeful that the Americans will put some money up to help Europe,” he said. “This is a moment to to make some investments will pay off in the long run.”