* Brent/WTI spread trades below $10 for 2nd day
* U.S. GDP expands at 2.5 pct annual rate, slower than expected
* Global oil inventories tightened in March-April -EIA
* Syria's possible use of chemical weapons stirs Gulf concerns (Adds U.S. GDP data, updates prices)
By Peg Mackey
LONDON, April 26 (Reuters) - Brent crude oil slid below $103 a barrel on Friday after rising $3 in the past two sessions as investors were cautious over the tepid outlook for growth in the world's two largest oil consumers, the United States and China.
The oil price is set for its biggest weekly gain since November but is still 7 percent off levels at the start of April after a string of disappointing data stoked fears of global economic slowdown.
Adding further pressure, data showed the U.S. economy grew less than expected in the first quarter, stoking worries about a deceleration in the second quarter.
Brent slipped 60 cents to $102.81 a barrel by 1313 GMT, after touching a low of $102.56, while U.S. crude was down 66 cents at $92.98.
"We had a sell-off when the GDP data came out," said Christopher Bellew, broker at Jefferies Bache. "And after a strong week, we're seeing quite a bit of profit-taking."
Despite oil's gains, some analysts said the market is still in a bearish mood.
"We know what is happening in Europe but we're uncertain about growth prospects in China and the U.S. and that's probably also why Brent is underperforming WTI (West Texas Intermediate)," said ANZ analyst Natalie Rampono.
Brent's premium to U.S. crude futures
"The market has gone through a period of relatively robust North Sea production, thus weakening the Brent side of the spread, while market participants are less concerned with the overhang of crude oil in the U.S. Midwest as the ability to move oil out of the region continues to increase," Dominick Chirichella of Energy Management Institute said.
Oil has also been supported by a tightening of global inventories over the past two months, according to a report from the U.S. Energy Information Administration, as well as by ongoing tensions in the Middle East.
Members of the U.S. Congress are calling for action on Syria after a report showed the likely use of chemical weapons by the Syrian government. (Additional reporting by Florence Tan in Singapore; editing by Jane Baird and Keiron Henderson)