With investors growing more nervous about the timing of the Fed's first rate hike in nearly a decade, the Dow dipped into negative territory for 2015.

Stronger-than-expected May jobs data released on Friday prompted expectations of a Fed rate hike in September, sooner than some expected.

“The May jobs number is pointing in the direction of a more likely interest-rate hike. The market is cringing at that idea," said Frank Davis, director of sales and trading at LEK Securities in New York.

Also weighing on U.S. investors, officials from Greece and the European Union met on Monday but there was little indication of progress to head off a potential Greek debt default when the country's bailout program expires at the end of June.

"The news flow continues to revolve around Greece," said Alan Gayle, senior investment strategist and director of asset allocation at RidgeWorth Investments in Atlanta. "We're of the opinion that a successful resolution to the Greek problem remains a coin toss."

The dollar retreated after a report – later denied – that President Barack Obama had expressed concern over its strength after a year-long rally.

The Dow Jones industrial average <.DJI> fell 82.91 points, or 0.46 percent, to end at 17,766.55. The S&P 500 <.SPX> lost 13.55 points, or 0.65 percent, to 2,079.28 and the Nasdaq Composite <.IXIC> dropped 46.83 points, or 0.92 percent, to 5,021.63.

Nine of the 10 major S&P sectors were lower, with the technology index's <.SPLRCT> 1.2 percent drop leading the losses.

With Monday's losses, the Dow is down 0.32 percent in 2015, while the S&P 500 is up a modest 0.99 percent and the Nasdaq is 6.02 percent higher.

Atmel Corp (>> Atmel Corporation) jumped 3.56 percent after Reuters reported the chipmaker is exploring strategic alternatives including a possible sale.

Apple (>> Apple Inc.) weighed most on the Nasdaq Composite and the S&P 500. It was down 0.66 percent to $127.80 after the iPhone maker unveiled a new music service.

Airlines stocks <.DJUSAR> fell 4.34 percent, with JetBlue (>> JetBlue Airways Corporation) slumping 7.22 percent. Qatar Airways asked the industry's largest trade group to address protectionism, hitting back against U.S. airlines campaigning to restrict competition from Gulf carriers.

Tesla (>> Tesla Motors Inc) rose 2.87 percent after plans for its Gigafactory got a boost from Panasonic's (>> Panasonic Corporation) move to start sending its employees to the plant, with manufacturing expected to begin next year.

Declining issues outnumbered advancing ones on the NYSE by 2,153 to 884, for a 2.44-to-1 ratio on the downside; on the Nasdaq, 1,785 issues fell and 1,004 advanced for a 1.78-to-1 ratio favoring decliners.

The S&P 500 posted 9 new 52-week highs and 9 new lows; the Nasdaq Composite recorded 131 new highs and 28 new lows.

About 5.5 billion shares changed hands on U.S. exchanges, below the 6.1 billion daily average so far in June, according to BATS Global Markets.

(Additional reporting by Tanya Agrawal; Editing by Savio D'Souza Editing by Nick Zieminski)

By Noel Randewich