Portugal Colonial - Stocks retreat over trade row; oil surges on geopolitical risks

The dollar was under pressure while Wall Street's main stock indices traded mixed, with the Dow and the broad-based S&P 500 dipping while the tech-heavy Nasdaq was flat in midday trading.

European stock markets finished mostly in the red, though London ended the day steady.

US President Donald Trump reignited tensions with China last week when he accused the world's second-biggest economy of violating a deal that had led both countries to temporarily reduce huge tit-for-tat tariffs.

Beijing rejected the "bogus" US claims on Monday and accused Washington of introducing "a number of discriminatory restrictive measures" against China since they agreed on a truce last month.

Trump also ramped up tensions with other trade partners, including the European Union, by vowing to double global tariffs on steel and aluminium to 50 percent from Wednesday.

"Trump's pledge to double steel and aluminium import tariffs have caused fresh uncertainty, especially with the European Union vowing to retaliate against the measures," said Susannah Streeter, head of money and markets at Hargreaves Lansdown.

"Negotiations between the US and China also appear to be in disarray."

The European Union on Saturday said it "strongly regrets" the tariffs move by Trump, warning it "undermines ongoing efforts to reach a negotiated solution" with the United States.

The EU added that it stood "ready" to retaliate.

The two sides are set for talks on the sidelines of an OECD ministerial meeting in Paris on Wednesday.

A US trade court ruling against the tariffs last week briefly buoyed the markets, but the decision was frozen pending an appeal and the Trump administration insisted that the levies would not go away.

"Overall, it feels as if investors are wary of adding to their exposure until they get more clarity on trade and tariffs," said David Morrison, senior market analyst at financial services firm Trade Nation.

The Hong Kong and Tokyo stock markets both ended with sizeable losses Monday. Shanghai was shut for a Chinese public holiday.

Oil prices surged, with the main US contract, WTI, briefing jumping by five percent.

The surge came after OPEC+ producers' grouping agreed on a smaller-than-expected increase in crude production.

"Traders had feared that OPEC+ would announce a significantly larger increase in production," Morrison said.

"Prices were also lifted by the increased military activity between Ukraine and Russia reported over the weekend. In addition, there were reports that the US may impose stricter sanctions on Moscow, and this helped boost prices."

Ukraine said Sunday that it hit dozens of strategic Russian bombers parked at airbases thousands of kilometres behind the front line.

Traders were also monitoring tensions over Iran's nuclear programme after Tehran said it would not accept an agreement that deprives it of what it calls "peaceful activities".

- Key figures at around 1540 GMT -

New York - Dow: DOWN 0.6 percent at 42,036.30 points

New York - S&P 500: DOWN 0.3 percent at 5,896.78

New York - Nasdaq Composite: FLAT at 19,109.61

Paris - CAC 40: DOWN 0.2 percent at 7,737.20 (close)

Frankfurt - DAX: DOWN 0.3 percent at 23,930.67 (close)

London - FTSE 100: FLAT at 8,774.26 (close)

Tokyo - Nikkei 225: DOWN 1.3 percent at 37,470.67 (close)

Hong Kong - Hang Seng Index: DOWN 0.6 percent at 23,157.97 (close)

Shanghai - Composite: Closed for a holiday

Euro/dollar: UP at $1.1434 from $1.1349 on Friday

Pound/dollar: UP at $1.3552 from $1.3463

Dollar/yen: DOWN at 143.34 yen from 143.97 yen

Euro/pound: UP at 84.39 pence from 84.30 pence

Brent North Sea Crude: UP 3.1 percent at $64.74 per barrel

West Texas Intermediate: UP 3.2 percent at $62.74 per barrel

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