WASHINGTON (NYTIMES) - The World Trade Organisation will grant the United States permission to impose tariffs on the European Union as part of a prolonged scuffle over subsidies given to European plane-maker Airbus, European officials said on Monday (Sept 16), a move that is likely to exacerbate trade tensions across the Atlantic.

The ruling, to be published in the week of Sept 30, is the global trade body's final decision in a 15-year-old dispute over the government assistance that Europe provides to its major plane manufacturer.

It will clear the way for the United States to impose tariffs on European goods, worsening tensions that have become strained under President Donald Trump's confrontational approach.

The WTO still must authorise a specific dollar amount that the United States can recoup through tariffs. But the US trade representative has already prepared two lists of up to US$25 billion (S$34.41 billion) worth of products that it can tax, including airplanes, fish, wine, leather purses, carpets and clocks.

The trade body opened the door for the Trump administration to impose billions of dollars in retaliatory sanctions in May, when it ruled that Europe had illegally subsidised Airbus to the detriment of its American competitor Boeing.

The ruling could become fodder for Mr Trump's growing trade fight with the European Union, which he has accused of weakening its currency and criticised for exporting more goods into the United States than it buys.

In retaliation for the harm Europe's trade actions have caused the US economy, the United States is proposing tariffs on a wide variety of European products, including helicopters, airplane fuselages, Parmesan cheese, olives, wine, handbags, sweaters, glassware, clocks, Irish and Scotch whisky, and copper alloys.

The US Trade Representative held hearings in May and August to allow companies and groups that might be affected by the tariffs to plead their case, and the final list could change.

The Trade Representative is expected to release the final list after the WTO announces its official decision.

Mr Trump has already rankled European leaders by imposing tariffs on steel and aluminium imports and threatening to tax European automobiles before the end of the year.

His administration's attempt to negotiate a trade deal with the bloc has also faltered as the two sides continue to disagree about which industries, like agriculture, should be included in any deal.

The Airbus ruling threatens to set off a tit-for-tat tariff exchange between the two major trading partners that may further weigh on trans-Atlantic business and global economic growth.

The WTO is also considering a parallel case that the European Union has brought against the United States for providing subsidies to Boeing.

The EU claims that the United States provided US$20 billion in illegal subsidies to Boeing, including through Washington state tax breaks.

A decision in that case is expected early next year and could authorise European retaliation against the United States.

The EU has already drawn up its own list of US$20 billion of American imports it plans to tax after the Boeing ruling is announced, including aircraft, food and chemicals.

Speaking in Brussels on Monday, Ms Cecilia Malmstrom, the outgoing European commissioner for trade, said the EU had tried to negotiate a way out of retaliatory tariffs, but the United States had not responded to these requests.

Ms Malmstrom said she had approached US officials "long before this summer" to discuss a resolution to the tariff spat.

"It's not that they said 'no', it's that they have not engaged on this, and we have provided them paper and proposals and so on," she said.

"We would propose that we both freeze or suspend our tariffs while we talk, until we come to an agreement, and that remains to be seen."

She added that both governments "need to discipline our air industries" and work to reform subsidies.

"And it would be good to do that together," she added.

"It is sometimes a little bit hard to predict the next step by the US administration," Ms Malmstrom said.

The US trade representative did not respond immediately for comment.

Ms Malmstrom also said on Monday that negotiations on a free trade agreement with the United States had stalled.

US officials want agricultural goods to be included in any trade discussion, saying that a deal that excludes farm goods was unlikely to be approved by Congress.

The European Union has refused to put agriculture on the table and pushed for the pact to cover industries where the two governments already agree, namely non-auto industrial goods.

European officials had hoped for a fresh start with the United States earlier this month, after a positive visit by Secretary of State Mike Pompeo to Brussels on Sept 2.

Ms Malmstrom said on Monday that Mr Gordon Sondland, the US ambassador to the European Union, had told her that the United States wanted to "restart" its relationship with the European Union.

But imposing tariffs on aircraft could make any resolution more difficult.

The Trump administration has already levied a 10 per cent tariff on aluminium and a 25 per cent tariff on steel from the European Union, and it is scheduled to make another decision about whether to impose tariffs on cars imported from Europe and elsewhere in November, taxes that could be devastating to major auto exporters like Germany.

Mr Trump decided in May to postpone those levies for six months, saying that his administration wanted to see how trade talks with Europe progressed.

The administration has cited national security as justification for the metal and auto tariffs, saying that imports have degraded the American industrial base, putting the country's ability to supply critical goods and technology to the military at risk.

That rationale has been controversial, and many critics argue that the tariffs violate the WTO's international trade rules.

New tariffs as a result of the Airbus case would be different, as the World Trade Organisation has permitted them.

The organisation allows its members to levy tariffs on each other to recoup trade losses when it finds a country has broken its trade rules.

Dr Chad Bown, a senior fellow at the Peterson Institute, said that tariffs on European exports in response to the Airbus decision would be very different legally from the tariffs on European steel and aluminium, though "neither is a good economic idea", he said.

"In the Airbus case, the US is imposing tariffs only after it went through all of the WTO's legal steps - proving its case and getting an official ruling - and only after Europe was asked and refused to comply," he said.