(Sharecast News) - US stock markets were expected to open flat to slightly lower on Wednesday amid heightened geopolitical tensions as Donald Trump steps up his expansionist rhetoric with threats to take over Greenland.

Futures on the Dow were trading 0.05% higher in pre-market deals, with upside limited after the benchmark settled at a new high of 49,462.08 on Tuesday. However, the S&P 500 was set to fall 0.15% from its record close of 6,944.82, while Nasdaq futures were pointing to a 0.34% decline.

Trump, who at the weekend ousted Venezuelan president Nicolas Maduro through a controversial cross-border military operation, has once again set his sights on Greenland as his next potential target, citing the region as a "national security priority".

The White House said the US president was looking at "a range of options" to take over the semi-autonomous Danish territory, and could potentially use military action to get what he wants.

"As well as pledging to turn over between 30 and 50 million barrels of Venezuelan oil to the US following the weekend strikes on the country, prompting concern about crude oversupply and pressuring prices, President Trump is looking at options to acquire Greenland - with military action apparently not ruled out," said AJ Bell's investment director Russ Mould.

"For now, the market doesn't appear to be too concerned that an attack will materialise, something Danish prime minister Mette Frederiksen has warned would spell the end of Nato. A modest retreat in gold and silver, traditional havens, also suggests investors are remaining sanguine for the time being."

Aside from geopolitics, the release of the ADP employment report for December - due at 1315 GMT - will be closely watched by investors, with market forecasts pointing to a 47,000 increase in private-sector payrolls last month, compared with a 32,000 reduction in November.

Traders will also be watching the latest releases covering US factory orders, mortgage applications and job openings, as well as the ISM services PMI.

Stocks to watch

Stocks across America's energy industry will be closely watched as markets continue to assess the implications of Trump's assault on Venezuela.

"President Trump's comments overnight that the US would primarily benefit from supply - with 50 million barrels expected to be bound for America - have muted expectations for both the oil price, which has fallen," said Emma Wall, chief investment strategist at Hargreaves Lansdown. WTI crude was down 0.5% at $56.87 a barrel early on.

Futures of Chevron, which remains the only remaining major American producer in Venezuela, were tracking higher after a sharp rise and subsequent fall over Monday and Tuesday. Oilfield services groups and refiners Valero, Phillips 66, SLB and Halliburton, who all made significant moves over the past two days, were also in focus.

Producers ExxonMobil and ConocoPhillips, which were in the red on Tuesday, were making small gains ahead of the opening bell.