The dollar plunged Thursday after US President Donald Trump threatened higher unilateral tariffs on trade partners, while oil prices fluctuated amid reports Israel might be preparing to strike Iran.

Stocks traded mixed as investors navigated the combined effects of renewed trade uncertainty and geopolitical volatility, with Boeing’s share price falling sharply following a deadly 787 Dreamliner crash in India.

In New York, investors welcomed benign US producer price data and a successful US Treasury auction that pushed yields lower.

But markets remained cautious after Trump said Wednesday he would be sending letters within the next two weeks to other countries’ governments to announce unilateral US levies on their exports.

"This is the deal, you can take it or leave it," Trump told reporters.

Investor unease about Trump’s trade rhetoric is "causing a little bit of selling," said Jack Ablin of Cresset Capital Management.

Despite volatility, the S&P 500 finished up 0.4 percent after a see-saw session.

All European stock markets finished lower except London, which posted a gain despite official data showing the UK economy shrank more than expected in April.

The dollar fell against the euro and at one point dropped more than one percent to its lowest level in three years against the European single currency.

"Trump has done it again. The US president has rattled markets with fresh threats of unilateral tariff rates on several trading partners," said Fawad Razaqzada, market analyst at FOREX.com.

Markets also tracked reports that Israel was poised to launch airstrikes on Iran.

Trump called Thursday on Israel not to attack Iran, saying a deal on its nuclear program remained close.

But Iran has ramped up rhetorical pressure before upcoming talks, including with a threat to strike American bases in the region if the negotiations break down and conflict erupts.

Oil prices, which initially jumped Wednesday on heightened tensions, reversed course Thursday to finish modestly lower.

In New York, Boeing shares dropped nearly five percent after a London-bound Air India Boeing 787 crashed in Ahmedabad with 242 people aboard.

The US planemaker declared itself ready to support Air India following the crash, the first involving a 787 Dreamliner.

Key figures at around 2015 GMT

New York - Dow: UP 0.2 percent at 42,967.62 (close)
New York - S&P 500: UP 0.4 percent at 6,045.26 (close)
New York - Nasdaq Composite: UP 0.2 percent at 19,662.49 (close)
London - FTSE 100: UP 0.2 percent at 8,884.92 (close)
Paris - CAC 40: DOWN 0.1 percent at 7,765.11 (close)
Frankfurt - DAX: DOWN 0.7 percent at 23,771.45 (close)
Tokyo - Nikkei 225: DOWN 0.7 percent at 38,173.09 (close)
Hong Kong - Hang Seng Index: DOWN 1.4 percent at 24,035.38 (close)
Shanghai - Composite: FLAT at 3,402.66 (close)

Euro/dollar: UP at $1.1583 from $1.1487 on Wednesday
Pound/dollar: UP at $1.3605 from $1.3547
Dollar/yen: DOWN at 143.56 yen from 144.56 yen
Euro/pound: UP at 85.11 pence from 84.79 pence

Brent North Sea Crude: DOWN 0.6% at $69.36 per barrel
West Texas Intermediate: DOWN 0.2 percent at $68.04 per barrel