President-elect Donald Trump on Friday threatened the European Union with tariffs if the bloc does not reduce its "tremendous" trade deficit with the United States through large oil and gas purchases.

The EU is already buying the lion's share of U.S. oil and gas exports, according to U.S. government data, and no additional volumes are currently available unless the United States increases output or volumes are re-routed from Asia – another big consumer of U.S. energy.

"I told the European Union that they must make up their tremendous deficit with the United States by the large scale purchase of our oil and gas," Trump said in a post, opens new tab on Truth Social.

"Otherwise, it is TARIFFS all the way!!!," he added.

The European Commission said it was ready to discuss with the president-elect how to strengthen an already strong relationship, including in the energy sector.

"The EU is committed to phasing out energy imports from Russia and diversifying our sources of supply," a spokesperson said.

The United States already supplied 47% of the European Union's LNG imports and 17% of its oil imports in the first quarter of 2024, according to data from EU statistics office Eurostat.

Trump has vowed to impose tariffs on most if not all imports, and said Europe would pay a heavy price for having run a large trade surplus with the U.S. for decades.

Trump has repeatedly highlighted the U.S. trade deficit for goods, but not trade as a whole.

The U.S. had a goods trade deficit with the EU of 155.8 billion euros ($161.9 billion) last year. However, in services, it had a surplus of 104 billion euros, Eurostat data shows.

Trump, who takes office on Jan. 20, has already pledged hefty tariffs on three of the United States' largest trading partners – Canada, Mexico and China.

Most European oil refiners and gas firms are private and the governments have no say on where the purchases are coming from unless authorities impose sanctions or tariffs. The owners usually buy their resources based on price and efficiencies.

The EU has steeply increased purchases of U.S. oil and gas following the block's decision to impose sanctions and cut reliance on Russian energy after Moscow invaded Ukraine in 2022.

The United States has grown to become the largest oil producer in recent years with output of over 20 million barrels per day of oil liquids or a fifth of global demand.

U.S. crude exports to Europe stand at over 2 million bpd representing over a half of U.S. total exports with the rest going to Asia. The Netherlands, Spain, France, Germany, Italy, Denmark, and Sweden are the biggest importers, according to the U.S. government data.

The United States is also the world's biggest gas producer and consumer with output of over 103 billion cubic feet per day (bcfd).

The U.S. government projects that U.S. exports of liquefied gas (LNG) will average 12 bcfd in 2024. In 2023, Europe accounted for 66% of U.S. LNG exports, with the U.K., France, Spain and Germany being the main destinations.

The EU had a trade surplus with the rest of the world in October of 3.9 billion euros, down from 8.4 billion euros in October 2023.

The EU's trade with the United States, the bloc's top trading partner, showed an overall surplus of 20.3 billion euros in October, up from 16.8 billion 12 months earlier.

EU exports are dominated by Germany with key goods being cars, machinery and chemicals.

Earlier this month, the European Union concluded a massive trade deal with four South American countries – Argentina, Brazil, Paraguay and Uruguay – which aims to create a 700-million-customer free-trade area.

European Commission Chief Ursula von der Leyen had said the agreement would build trade bridges as "strong winds are blowing in the opposite direction, towards isolation and fragmentation" – comments largely seen as a nod to Trump's threats to hike tariffs.

Some analysts have said Trump's tariff threat could be bluster, or an opening shot for leverage in future trade negotiations when he comes into office.

But Trump has continually insisted that "properly used" tariffs would be positive for the U.S. economy.

"Our country right now loses to everybody," he told reporters at his Florida residence earlier this week. "Tariffs will make our country rich."