The United States and European Union said Friday they are working together on guaranteeing Europe's energy security as well as Ukraine's amid the standoff triggered by Russia amassing troops at Ukraine's border.

They are "working jointly towards 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," said a statement from U.S. President Joe Biden and EU chief Ursula von der Leyen.

Russia has massed an estimated 100,000 troops within reach of Ukraine's border, surrounding it from the north, east and south, raising alarm in the West that Moscow is preparing for a new military assault after its invasion of Crimea in 2014.

The Russian government denies that it plans an invasion and Moscow has cited the Western response as evidence that Russia is the target, not the instigator, of aggression.

The European Union depends on Russia for around a third of its gas supplies. Any interruptions to Russia's gas supply to Europe would exacerbate an existing energy crisis caused by a shortage.

The United States has been in talks with major energy-producing countries and companies around the world over a potential diversion of supplies to Europe if Russia invades Ukraine, senior Biden administration told reporters earlier this week.

Reuters previously reported that State Department officials were discussing contingency plans with energy companies to ensure stable supplies to Europe if conflict between Russia and Ukraine disrupted Russian supplies.

The plan to ensure adequate supplies to Europe is complicated by the fact that the world's LNG producers are already churning out as much as they possibly can.