UPDATE 8-Brent tumbles on strong dollar, Iran talks; spread narrows
* West seeks first-step deal with Iran in Geneva talks
* ECB cuts rates to new low
* U.S. dollar strengthens
(New throughout, updates prices and market activity)
NEW YORK, Nov 7 (Reuters) - Brent crude oil futures slid to a four-month low on Thursday, pressured by a strong dollar, plentiful supplies and continued progress in talks between Iran and the West over Tehran's disputed nuclear program.
Brent has fallen nearly 2 percent this week, on track for its fourth straight weekly decline. Its premium over West Texas Intermediate, the U.S. oil benchmark, also narrowed.
A move by the European Central Bank to cut interest rates to a record low boosted the dollar, making dollar-denominated crude more expensive for buyers outside the United States.
The dollar rose further against the euro and yen after the U.S. Commerce Department said U.S. economic growth accelerated more than expected in the third quarter.
The spread between Brent and U.S. crude narrowed by more than $1 during the session, in what analysts said could also be a currency play.
"You might see Brent drop quicker and further because Brent is generally traded in euros, and they have an easy money policy," said Rich Ilczyszyn, chief market strategist at iitrader.com in Chicago.
Brent fell $1.40 to $103.84 a barrel by 1:08 p.m. EST (1808 GMT). U.S. oil slipped 37 cents to $94.43 a barrel, after posting an earlier low of $93.80.
Brent's premium over WTI <CL-LCO1=R> was last trading at $9.41 per barrel, after narrowing from the previous session's settlement by as much as $1.29 to $9.15 earlier in the session.
Iran and six world powers are making progress in talks aimed at ending a decade-long nuclear stand-off between Tehran and the West, but the discussions are "tough", Iran's foreign minister said on Thursday.
"The weak euro and stronger dollar are obviously in play, and it looks like these Iran talks are going to cement a deal," said Phil Flynn, an analyst with the Price Futures Group in Chicago, Illinois.
Although both sides in the Iran negotiations say an agreement is far from certain, Iran's Foreign Minister Mohammad Javad Zarif said a deal is possible "if everybody tries their best".
Investors will watch U.S. nonfarm payroll data on Friday to gauge when the Federal Reserve might begin winding down its $85 billion-a-month bond-buying program.
An excess supply in the physical market is reflected in Brent futures LCOc1, where the December contract is now trading at around a 15-cent discount to the January contract.
"As more supply has come into the market, now the front end has slipped into contango, and margins are not particularly healthy," said Andy Lebow, vice president at Jefferies Bache in New York.
"In the last couple of weeks, the market has not been looking to any exogenous factors. It's been responding to its own fundamentals."
(Additional reporting by Jeanine Prezioso in New York, Peg Mackey in London, Manash Goswami in Singapore; editing by Keiron Henderson, Jane Baird and David Gregorio)