Stocks closed in positive territory on Thursday but lingering worries over a possible U.S. military strike on Syria put a damper on the markets.
Stocks were higher for most of the day, boosted by a pair of stronger-than-expected economic reports, but slipped later in the afternoon.
(Read more:Selling on Syria likely short-lived, going by history)
The Dow Jones Industrial Average eked out small gains and ended the day just 16 points ahead, led by Verizon and Boeing. ExxonMobil led the decliners.
The S&P 500 and the Nasdaq also closed with slight gains. The CBOE Volatility Index (VIX), widely considered the best gauge of fear in the market, gained near 17.
Among the key S&P sectors, telecoms rallied, while energy fell.
"There are a number of resistance levels that the S&P will face on this rally: the 50-day moving average at 1,660, down trend line resistance at 1,670 and the gap at 1,685," said Elliot Spar, market strategist at Stifel Nicolaus. "It doesn't seem like a tall order but the technical damage done to so many individual stocks will probably make this rally to resistance levels labored for many names."
(Read more: Gundlach: This market is just 'fear and loathing')
On the economic front, weekly jobless claims declined 6,000 to a seasonally adjusted 331,000, according to the Labor Department. Economists polled by Reuters had expected first-time applications to fall to 332,000 last week.
And the U.S. economy accelerated more quickly than expected in the second quarter to a 2.5 percent annual rate, according o the Commerce Department, giving further support for the Federal Reserve to wind down its asset-purchase program as soon as next month. The government had initially estimated that GDP expanded at a 1.7 percent rate in the second quarter.
"The GDP print should be considered 'less-bad' rather than positive, especially when considering the headwinds facing American consumers in the second half of the year: evaporation of personal savings and a deceleration of wages," said Todd Schoenberger, managing partner of LandColt Capital. "The headline number may provide a short-term boost in the markets, but investors should consider the fragile future for growth in the U.S."
The Treasury auctioned $29 billion in 7-year notes at a high yield of 2.221 percent. The bid-to-cover ratio, an indicator of demand, was 2.43, compared to a recent average of 2.65.
In a TV interview, President Obama said he remained undecided on whether to take military action against Syria, but added that a "tailored, limited" military strike could be enough to deter any future use of chemical weapons.
In Europe, Britain's Ministry of Defense said it was sending 6 Typhoon fighter jets to Cyprus as a precautionary measure while Parliament debated the ossibility of military action against Syria.
Speculation over a strike pushed oil prices higher on Wednesday, which boosted U.S. energy stocks and helped reverse two-straight sessions of losses on Wall Street.
Meanwhile, the Nasdaq said its massive trading halt last week was due to an internal software bug and other technology issues triggered by problems at NYSE Euronext's Arca exchange that led to the failure of a key backup system.