By Caroline Valetkevitch

NEW YORK (Reuters) -U.S. stocks ended slightly lower on Tuesday as tariff uncertainty stayed high and shares of consumer and healthcare companies eased, while upbeat results from banks provided some support.

Shares of Bank of America and Citigroup rose following their results.

Still, bank executives warned that U.S. consumer spending faces huge risks if the upheaval sparked by President Donald Trump's trade policy goes on.

Among the biggest weights on the Dow was Boeing. The stock fell 2.4% after Bloomberg reported, citing people familiar with the matter, that China has ordered its airlines not to take further deliveries of Boeing jets in response to the U.S. decision to impose 145% tariffs on Chinese goods.

Federal Register filings on Monday showed the Trump administration was also proceeding with probes into imports of pharmaceuticals and semiconductors, as part of a bid to impose tariffs on the sectors.

Trump's April 2 announcement of sweeping tariffs sparked turmoil in the market and fueled worries about a global trade war and possible recession. Trading has been more subdued this week, but investors have been unable to focus on much else.

"Earnings have been pretty good, but this is a market that's just beset by tariff and trade uncertainty and those are really the only catalysts that matter at this point," said Ross Mayfield, investment strategist at Baird in Louisville, Kentucky.

"On a day where you're bereft of those (catalysts), it's kind of a wayward market, and we're seeing that today."

Johnson & Johnson's shares ended down 0.5% after the company missed estimates for sales of medical devices, despite beating Wall Street estimates for first-quarter revenue and profit.

Barclays on Tuesday downgraded the U.S. auto and mobility sector, saying Trump's tariffs could pressure automakers' earnings. Shares of Ford closed down 2.7% while shares of General Motors fell 1.3% and the S&P consumer discretionary index slipped 0.8%.

The Dow Jones Industrial Average fell 155.83 points, or 0.38%, to 40,368.96, the S&P 500 lost 9.34 points, or 0.17%, to 5,396.63 and the Nasdaq Composite lost 8.32 points, or 0.05%, to 16,823.17.

Also in the healthcare space, shares of Merck & Co ended 1% lower.

Bank of America topped estimates for first-quarter profit as interest income grew, and its shares ended up 3.6%.

S&P 500 companies have just begun to report results for the quarter ended March 31, but changes in U.S. trade policy are muddying the outlook and executives could be reluctant to give earnings guidance.