The EU and the United States have fought for over a decade over mutual claims of illegal aid to plane giants Boeing and Airbus.
Washington said it would impose the tariffs under the same previously dormant trade statute that it has used to justify duties on China over the past year.
The letter of objection was signed by Indonesian President Joko Widodo and Prime Minister Dr Mahathir Mohamad.
The WTO said global trade is likely to grow by 2.6% this year, slower than the 3% growth seen in 2018 and below a previous forecast of 3.7%.
China has challenged the Trump administration's tariffs in the WTO, arguing that they violate its agreed rules.
USTR says US intends to hold China accountable for adhering to existing WTO rules and any unfair and market-distorting trade practices that hurt US workers, businesses, farmers or ranchers.
The EU accounted for around 15% of Indonesia's total palm exports of more than US$15 billion last year.
If successful, a digital trade accord would establish a baseline international regime for 21st-century trade and reduce cross-border hurdles to e-commerce.
Trump's administration has attacked the WTO on multiple fronts, including its alleged failure to respond to the Beijing's manipulation of free enterprise.
US trade ambassador Dennis Shea said reforms are necessary for the continued viability of the WTO.
With the odds stacked against her in Parliament and EU ministers saying there’s no Plan B, May could well be out of options.
Even the word 'multilateralism' itself has fallen out of favour in a group designed to foster international cooperation.
New restrictions covered six times more trade than in the previous period and were the largest since the WTO started monitoring G20 trade in 2012.
The United States insistence that members of APEC agree to publicly criticise the WTO -- saying the organisation is not working and needs major reform -- has prompted Chinese opposition.
A surge in global protectionism from Brexit to the US-China trade war has done little to dent foreign direct investment flows overall, according to data presented to the XBMA conference on cross-border mergers and acquisitions.
China's Premier Li Keqiang will meet the heads of the IMF, the World Bank and the World Trade Organization as well as the Organization for Economic Co-operation and Development in Beijing.
US Ambassador Dennis Shea told the WTO's monthly dispute settlement meeting, which was considering 12 requests for adjudication over US tariffs and related retaliation, that Washington was deeply disappointed with the EU's stance.
Absent from the meeting are the United States and China, whose escalating tariff war has thrown the future of the 23-year-old trade body into doubt.
The EU, China and the US escalated disputes over new US metals tariffs, the European response to those levies, and Chinese intellectual property practices.
The move sets the stage for a showdown at the Geneva-based trade arbiter that some fear could either lead to a US exit or a flood of new protectionist measures.
World leaders are now struggling to find common ground.
Blockchain, artificial intelligence, the internet of things, 3D printing and other breakthroughs would fundamentally change trade, WTO Director-General Roberto Azevedo said.
Saudi officials were not immediately available to comment. They have previously said that the country is taking action to combat piracy and is committed to protecting intellectual property rights.
WTO Director-General Roberto Azevedo warned that a full-blown trade war "would knock around 17% off global trade growth, and 1.9% off GDP growth."