U.S. Treasury Secretary Janet Yellen said the United States and Europe needed to “go further” in confronting Russia’s war against Ukraine, while expanding the “potent transatlantic cooperation to address many of the other shared challenges we face.”

Speaking at the Brussels Economic Forum on Tuesday, Yellen said “we must address the present energy security emergency to ensure supply for Europe and the world, while using this as our moment to rapidly accelerate the transition to clean energy.”

In a bid to limit Russian energy flows, the White House said it would send another 15 billion cubic meters (Bcm) of liquefied natural gas (LNG) to Europe this year and 50 Bcm annually through at least 2030. The United States also has pledged to expedite approvals for LNG...