The US dollar strengthened on Wednesday while Wall Street stocks were mixed after the US Federal Reserve indicated its latest interest rate cut might not be repeated in December.

After the US central bank announced a quarter percentage-point interest rate cut that had been expected, Fed Chair Jerome Powell told reporters that another decrease in December "is not a foregone conclusion, far from it."

The statement jolted US indices, lifting the dollar and pushing all three US equity markets briefly into the red.

The Nasdaq later recovered, finishing at a fourth straight record behind another gain by artificial intelligence giant Nvidia, which became the first company to reach a US$5 trillion market value.

The Dow finished modestly lower while the S&P 500 ended flat.

Oxford Economics characterised Powell as "hawkish," predicting that the central bank would "move to the sidelines" and not cut again until March.

Powell also indicated in his press conference that the dearth of economic data due to the US government shutdown could also prompt more cautious policy making.

The Dow had earlier topped 48,000 points following fresh peaks set in London and some Asian markets as US President Donald Trump voiced optimism on the eve of crunch trade talks with President Xi Jinping.

Trump predicted a "great meeting," while China's foreign ministry was more cautious, saying that Xi and Trump would have "in-depth" talks on "major issues."

The two leaders are set to meet on Thursday in Busan, a southern port city not far from the Apec summit attended by Trump.

US industrial giant Caterpillar surged 11.6 percent after reporting better than expected profits, partly due to strong demand in its energy & transportation business partly related to heavy AI infrastructure investment.

The Dow Jones edged down 0.2 percent to 47,632. The S&P 500 ended essentially flat at 6,890, while the Nasdaq rose 0.6 percent to 23,958. (AFP)