The International MonetaryFund warned world economic leaders on Saturday that arecent wave of trade tariffs would significantly harm global
growth, a day after U.S. President Donald Trump threatened amajor escalation in a dispute with China.

IMF Managing Director Christine Lagarde said she wouldpresent the G-20 finance ministers and central bank governorsmeeting in Buenos Aires with a report detailing the impacts ofthe restrictions already announced on global trade.

“It certainly indicates the impact that it could have on GDP , which in the worst case scenario undercurrent measures … is in the range of 0.5 percent of GDP on aglobal basis,” Lagarde said at a joint news conference withArgentine Treasury Minister Nicolas Dujovne.

In the briefing note prepared for G-20 ministers, the IMFsaid global growth might peak at 3.9 percent in 2018 and 2019,while downside risks have increased because of the growing tradeconflict.

Her warning came shortly after the top U.S. economicofficial, Treasury Secretary Steven Mnuchin, told reporters inthe Argentine capital there was no “macro” effect yet on theworld’s largest economy.

Long-simmering trade tensions have burst into the open inrecent months, with the United States and China — the world’s largest and second-largest economies — slapping tariffs on $34billion worth of each other’s goods so far.

The weekend meeting in Buenos Aires comes amid a dramaticescalation in rhetoric on both sides. Trump on Friday threatenedtariffs on all $500 billion of Chinese exports to the UnitedStates.

Mnuchin said that while there were some “micro” effects, such as retaliation against U.S.-produced soybeans, lobsters andbourbon,he did not believe that tariffs would keep the UnitedStates from achieving sustained 3 percent growth this year.

“I still think from a macro basis we do not…