* U.S. new unemployment claims fell 20,000 last week
* ECB leaves interest rates unchanged
* U.S. gasoline prices rise on seasonal trade
(Rewrites top, updates prices, spread, adds analyst quote)
NEW YORK, Feb 6 (Reuters) - U.S. crude oil futures were slightly higher in late afternoon trade Thursday, retreating from the session high on concerns that seasonal refinery maintenance will reduce demand.
U.S. crude was up 24 cents at $97.62 a barrel at 1:56 p.m. EST (1856 GMT), after rising as high as $98.83.
Brent for March delivery was trading 57 cents higher at $106.81 a barrel. Brent reached a high of $107.30 earlier in the session after the ECB said it would leave interest rates unchanged.
The American benchmark's decline pushed Brent's premium past $9, a day after it had contracted to less than $8.
Earlier, U.S. crude rose more than $1 a barrel on strong U.S. economic data, rising U.S. gasoline futures and strikes at oil ports in France that curbed supplies.
"We're in peak (refinery) turnaround season now, which translates into weak demand," said Stephen Schork, editor of the Schork Report in Villanova, Pennsylvania.
Analysts anticipate the U.S. benchmark will face resistance at the 200-day moving average of $99.34.
The number of Americans filing new claims for unemployment benefits fell slightly more than expected last week, according the U.S. Labor Department said.
U.S. gasoline prices rose more than 1 percent on the back of rising renewable identification number prices and a seasonal selloff in heating oil as traders move to gasoline futures ahead of the summer driving season.
A 24-hour strike on Thursday in France blocked the oil hub of Fos-Lavera, cutting into supply and supporting Brent.
Brent drew support as the euro rose to a one-week high against the U.S. dollar after the ECB said it would leave interest rates unchanged.
"With the supply dropping and the ECB's comments...we're seeing Brent prices jumping on this rally," said Matt Smith, analyst at Schneider Electric in Louisville, Kentucky.
U.S. crude drew support from snow and ice storms in the northeastern U.S. states, which boosted demand for heating fuels.
In spite of cold weather demand, U.S. ultra-low sulfur diesel (ULSD) traded slightly lower on Thursday at $2.9904 per gallon.
U.S. gasoline futures rose 4 cents to trade at $2.6747 per gallon as traders bought contracts to cover short positions.
"There are a couple seasonal long trades in gasoline - the first in December and the second in January," said Bill Baruch, senior market strategist at iitrader.com in Chicago. "There are now shorts in the market as all the energies rise and now they're buying to close their position."
The spread between U.S. crude and Brent <CL-LCO1=R> last traded at $9.23 a barrel. On Wednesday, the spread narrowed to $7.94 per barrel, the tightest it has been since Oct. 10.
Ongoing supply disruptions in Libya, where exports of around 600,000 barrels per day are still cut off by protests, continued to set a floor for Brent prices.
(Additional reporting by David Sheppard in London and Jacob Gronholt-Pedersen in Singapore; Editing by Dale Hudson, David Evans, Peter Galloway and David Gregorio)