NEW YORK (AFP) - Wall Street stocks scraped out narrow gains on Tuesday (Feb 19) on strong Walmart earnings and continued optimism over US-China trade talks.

The Dow Jones Industrial Average finished a choppy session up less than 0.1 per cent at 25,891.32.

The broad-based S&P 500 gained 0.2 per cent to 2,779.76 and the tech-rich Nasdaq Composite Index also advanced 0.2 per cent to 7,486.77.

US and Chinese officials resumed high-stakes negotiations in Washington aimed at ending a damaging tariff war between the economic superpowers.

US President Donald Trump said the talks were "going very well" but are "very complex."

He suggested he could extend a March 1 deadline to impose new tariff measures if a final deal is not reached in time, saying the start of the next month is "not a magical date".

Art Hogan, chief market strategist at National, said investors remain encouraged by the current state of talks between the two countries.

"The perception is negotiations continue," he said. "We're not there yet but if we get to the deadline, the situation won't escalate."

Hogan also cited Walmart earnings as a positive. The world's biggest retailer reported a nearly 70 per cent jump in fourth-quarter profits to US$3.7 billion (S$5 billion) following strong holiday sales. The retailer led the Dow with a 2.2 per cent increase.

The Walmart earnings were reassuring after a disappointing December US retail sales report released last week.

The S&P 500 has risen about 18 per cent since Dec 24, a rally that some analysts think could set the stage for profit taking or sideways movement.

Besides the trade talks, investors are eyeing minutes from the Federal Reserve's last policy meeting, which will be released on Wednesday.

The US central bank shifted to a more dovish posture at the last meeting, a key factor in the stock market's rally since late December.