Global stock markets wobbled Friday as US President Donald Trump eyed further tariffs even as roadblocks emerged on striking a key trade deal with Canada.
Meanwhile, US stocks were essentially flat on the last trading day of August, heading into the long holiday weekend.
Markets closed before the news emerged that US-Canada talks ended without an agreement on rewriting the North American Free Trade Agreement, but will resume next week.
Even so, the US is pressing ahead with plans to sign a free trade deal with Mexico, and with Canada if talks are successful. Optimism about the talks had sent US stocks to four record-setting closes earlier in the week.
But by Friday the benchmark Dow and the broad S&P 500 were barely moved. US markets will be closed Monday for the Labor Day holiday.
A report that Trump is planning to impose tariffs on a further $200 billion of Chinese imports as soon as next week jolted trading floors in Europe and Asia.
European Commission chief Jean-Claude Juncker on Friday warned that the European Union would hit back with tariffs of its own, should Trump make good on threats to slap duties on foreign cars, as cracks emerged in an EU-US trade truce.
And in an interview with Bloomberg on Thursday, Trump threatened to pull the United States out of the World Trade Organization if it does not "shape up."
Against this backdrop, foreign exchange traders dumped emerging market currencies after Argentina's peso became the latest to hit the buffers on concerns about the country's economy.
"There had been some hopes the US signing a trade deal with Mexico earlier in the week meant things were perhaps moving in the right direction," said Connor Campbell, analyst at Spreadex traders.
"However, with reports that Trump is looking to impose additional tariffs on China, his threat to pull the US out of the WTO and the tense, terse situation with both the EU and Canada, the markets are back to fretting about his next move."
Elsewhere, attention was firmly on Argentina, whose peso currency hit a record low near 40 to the dollar on Thursday.
Even if it made slight gains against the dollar, the peso has still lost more than 50 percent of its value since the start of the year as the government of President Mauricio Macri faces a financial catastrophe.
The IMF said Argentine officials will travel to Washington on Tuesday for talks to revise the $50 billion loan agreement and accelerate payments.
Turkey's lira also ticked higher after the government made it more expensive to hold foreign currency savings, a day after heavy selling following the resignation of a deputy central bank governor. The currency has lost more than 40 percent of its value this year.
The flight out of emerging market units hit India, where the rupee fell to 71 against the dollar for the first time. The embattled currency has lost about 10 percent this year.
And the Indonesian rupiah also dived, briefly hitting the 14,750 to the dollar mark seen during the Asian financial crisis in 1998.
"The spillover from the resurfacing emerging-market turmoil in the Argentina peso and Turkish lira is weighing on EM Asia currencies," said Ken Cheung, senior FX strategist at Mizuho Bank in Singapore.
In Europe, equities ended sharply lower. London dropped 1.1 percent, Frankfurt shed 1.0 percent and Paris fell 1.3 percent.
Key figures around 2100 GMT
New York - Dow Jones: DOWN 0.1 percent at 25,964.82 points (close)
New York - S&P 500: FLAT at 2,901.52 (close)
New York - Nasdaq: UP 0.3 percent at 8,109.54 (close)
London - FTSE 100: DOWN 1.1 percent at 7,432.42 (close)
Frankfurt - DAX 30: DOWN 1.0 percent at 12,364.06 (close)
Paris - CAC 40: DOWN 1.3 percent at 5,406.85 (close)
EURO STOXX 50: DOWN 1.2 percent at 3,390.80
Tokyo - Nikkei 225: FLAT at 22,865.15 (close)
Hong Kong - Hang Seng: DOWN 1.0 percent at 27,888.55 (close)
Shanghai - Composite: DOWN 0.5 percent at 2,725.25 (close)
Euro/dollar: DOWN at $1.1599 from $1.1666 at 2100 GMT
Pound/dollar: DOWN at $1.2961 from $1.3009
Dollar/yen: UP at 111.02 yen from 111.01 yen
Oil - Brent Crude: DOWN 47 cents at $77.30 per barrel
Oil - West Texas Intermediate: DOWN 37 cents at $69.88.