Voicing “serious concern,” the World Trade Organization (WTO) said Thursday that the world’s largest economies imposed import restrictions on nearly half a trillion dollars’ worth of trade over the past six months.

A new WTO report shows that 40 new import barriers were erected by G20 states between mid-May and mid-October this year – six times more than during the preceding six months – impacting $481 billion in trade.

That was the highest figure recorded since the WTO began calculating the measure in 2012.

“The report’s findings should be of serious concern for G20 governments and the whole international community,” WTO chief Roberto Azevedo said in a statement.

Calling for an immediate reversal of the trend, he warned that “further escalation remains a real threat.”

He added, “If we continue along the current course, the economic risks will increase, with potential effects for growth, jobs and consumer prices around the world.”

The report shows that an average of eight new restrictions on international trade, including tariff increases, import bans and export duties, were imposed by the largest economies each month.

The report highlights the impact of US President Donald Trump’s belligerent approach to trade policy, including starting a trade war with China and slapping high tariffs on steel and aluminum imports from many countries.

The WTO’s Dispute Settlement Body agreed on Wednesday to review complaints from a range of countries over the US tariffs, as well as Washington’s complaints about retaliatory duties.

Azevedo said, “The WTO is doing all it can to support efforts to de-escalate the situation, but finding solutions will require political will and it will require leadership from the G20.”

– With reporting from Agence France-Presse