* Q3 GDP revised up more than expected; jobless claims fall
* Lower U.S. crude stocks support U.S. oil
* OPEC keeps production target unchanged
* John Kerry: core sanctions against Iran remain in place despite interim deal
(Recasts with U.S. data, updates prices, adds Brent premium to U.S. oil, disruption in the North Sea)
LONDON, Dec 5 (Reuters) - Brent crude oil slipped towards $111 a barrel on Thursday, as traders weighed whether positive U.S. data would prompt the Federal Reserve to start curbing its monthly bond-buying programme.
U.S crude extended gains for a fifth day, narrowing its discount to Brent to its lowest level for two weeks.
U.S. gross domestic product grew at a revised 3.6 percent annual rate, up from a 2.8 percent pace reported earlier and above the 3.0 percent expected by economists polled by Reuters.
Initial claims for state unemployment benefits fell by 23,000 to a seasonally adjusted 298,000, declining for a third straight week.
"The positive data is a double-edged sword," said Commerzbank senior oil and commodities analyst Carsten Fritsch.
"On the one hand, it's positive for demand prospects. But on the other, it increases the likelihood that the Fed will taper sooner than later. It's not yet clear for which side the oil market will decide."
Brent crude oil for January delivery was down 60 cents at $111.28 a barrel at 1424 GMT.
U.S. crude was 6 cents higher at $97.26 per barrel, after rising more than a dollar on Wednesday and more than 5 percent over the past four sessions, putting the U.S. benchmark on course for its biggest weekly gain since July.
Brent's premium over U.S. crude, or West Texas Intermediate (WTI) <CL-LCO1=R>, hit a two-week low of $13.86 a barrel.
Supporting U.S. oil were figures from the Energy Information Administration (EIA) showing crude stocks fell by 5.6 million barrels in the week ended Nov. 29, cutting around one-sixth of the 36 million barrels that had built up over the previous 10 weeks.
Crude oil production in the United States dipped slightly last week but held above 8 million barrels per day (bpd), the data showed.
Brent crude oil prices were supported by assurances from U.S. Secretary of State John Kerry to Israeli Prime Minister Benjamin Netanyahu that core sanctions against Iran, including oil exports, would remain in place despite its interim nuclear deal with world powers.
Traders were also eyeing hurricane-force winds in the North Sea that threatened to disrupt oil supplies from the region. So far, however, only one small oil platform has been shut by the storm.
The Organization of the Petroleum Exporting Countries (OPEC) agreed on Wednesday to keep its production target unchanged at 30 million bpd for the first half of 2014.
Expectations of higher output from some OPEC members in the coming months and a continued increase from supplies in North America have left some traders questioning whether the producer group will need to curb output in the second half of 2014.
(Additional reporting by Jacob Gronholt-Pedersen in Singapore; editing by Jason Neely)