WASHINGTON (BLOOMBERG) - US stocks were slightly lower on Tuesday, weighed down by financial and technology shares, and as investors braced for a potentially tense meeting between President Donald Trump his and Chinese counterpart Xi Jinping.

Mr Trump, known to have a protectionist stance on trade, has held out the possibility of using trade as a lever to secure China's cooperation against North Korea when he meets Jinping on Thursday and Friday.

Adding to investors' jitters is the Trump administration's recent struggles to push legislation through Congress, particularly a healthcare reform bill. That has led to questions whether Mr Trump could deliver on his promises of tax cuts, looser regulations and higher spending on infrastructure, pro-business economic stimulus plans that has helped power the major US stock indexes to record highs.

"Traders are keeping a close political watch on the various upcoming events and are not likely to increase risk ahead of what may turn out to be a critical Trump, Xi meeting," Peter Cardillo, chief market economist at First Standard Financial wrote in a note.

At 9:37 a.m. ET (9:37 GMT), the Dow Jones Industrial Average was down 21.82 points, or 0.11 per cent, at 20,628.39, the S&P 500 was down 4.6 points, or 0.20 per cent, at 2,354.24 and the Nasdaq Composite was down 7.90 points, or 0.13 per cent, at 5,886.79.

Nine of the 11 major S&P 500 sectors were lower. The S&P technology sector was off 0.32 per cent, weighing the most on the benchmark index.