President Joe Biden on Friday pledged to work with the European Union to ensure energy security in Europe if Russia invades Ukraine.

Biden and European Commission President Ursula von der Leyen released a joint statement saying they are working toward “continued, sufficient, and timely supply of natural gas to the EU from diverse sources across the globe to avoid supply shocks, including those that could result from a further Russian invasion of Ukraine.”

Russia provides about a third of the European Union’s gas supplies, and Western officials fear Moscow could cut off the gas if it’s sanctioned for an incursion into Ukraine.

Russia has amassed 100,000 troops near Ukraine’s border but denies that it is planning an invasion.

As a precaution, Western officials have been working to find alternatives should Russia withhold its energy supplies.

White House press secretary Jen Psaki said this week the U.S. has been “engaging our European allies to coordinate response planning, including how to deploy their existing energy stockpiles.”

Psaki said U.S. officials also have been working to identify additional volumes of gas from North Africa, the Middle East, Asia and the United States. Talks also have been held with major natural gas producers, buyers and suppliers around the world to determine if they could temporarily divert supplies to Europe, she said.

“More broadly, we call on all major energy producer countries to join us in ensuring world energy markets are stable and well-supplied,” the statement by Biden and von der Leyen said.

Psaki stressed that, because natural gas markets are typically regional, any reduction in Russian exports of natural gas to Europe would be expected to have minimal impact on prices in the U.S.