The United States and European Union have said they are working together to source alternative supplies of natural gas to protect the EU in case key energy supplier Russia retaliates against sanctions.

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," a statement from President Joe Biden and EU chief Ursula von der Leyen said.

Russia supplies about 40% of the natural gas used in Europe, where prices are already rocketing and winter is far from over.

With Washington and European NATO allies threatening to impose crippling sanctions on Russia, if it attacks Ukraine, there are fears that Moscow could use its energy dominance as leverage.

The White House is leading a search for back-up supplies, including liquid natural gas, which is transported by ship.

US officials say that some exports previously destined for Asia from the Middle East have already been re-sold and diverted to Europe.

"We are collaborating with governments and market operators on supply of additional volumes of natural gas to Europe from diverse sources across the globe," the joint US-EU statement said.

Ireland not directly impacted

Tánaiste Leo Varadkar told the Dáil yesterday that Ireland uses very little gas from Russia.

Mr Varadkar said that his departmental officials had examined the issue and concluded that "Ireland doesn't use very much Russian gas".

Half of Ireland's gas is sourced domestically, he said, with the other half mainly coming through Britain.

He acknowledged, though, that there would be a knock-on effect for Ireland if supplies were cut globally.