The services data comes on the heels of Friday's better-than-expected April jobs report. Trade data is due on Tuesday in Washington.
In corporate news, shares of Pfizer fell, last down 2.7 per cent, as revenue disappointed at a time the company is pursuing a takeover of the UK's AstraZeneca which, if successful, would rank as one of the biggest deals ever.
Shares of Target also dropped, last down 3.2 per cent, after the company said Gregg Steinhafel would step down, effective immediately, from his role as CEO. CFO John Mulligan has been appointed interim president and CEO until a replacement has been found. Target is trying to recover from a data breach scandal in 2013.
In Europe, the Stoxx 600 Index ended with a decline of 0.3 per cent from the previous close, as did Germany's DAX. France's CAC 40 eked out a 0.1 per cent gain. Trading in London was closed today for the May Day holiday.
The European Commission tweaked its growth outlook for the euro region, saying it now is forecasting economic expansion at 1.7 per cent in 2015, compared with an earlier 1.8 per cent forecast. Inflation will remain stubborn at 0.8 per cent in 2014 and 1.2 per cent in 2015, below the European Central Bank's target of 2 per cent.
The intensifying conflict in eastern Ukraine weighed on equity markets on both sides of the Atlantic, while adding to the appeal of bullion. Gold futures for June delivery gained 0.5 per cent to settle at US$1,309.30 in New York.
"The rising tension in Ukraine is adding to investors' reduced risk appetite," Kai Fachinger, a money manager at RobecoSAM in Zurich, told Bloomberg News.