* West seeks first-step deal with Iran in Geneva talks
* Iran says deal possible "if everybody tries their best"
* Coming up: U.S. advance Q3 GDP; 1330 GMT
* Euro zone recovery lost momentum in Oct, Germany shines (Updates previous SINGAPORE)
LONDON, Nov 7 (Reuters) - Brent crude fell below $105 a barrel on Thursday to its lowest since early July as plentiful supplies and continued progress in talks between Iran and the West over Tehran's disputed nuclear programme weighed on prices.
Investors are also awaiting the outcome of the European Central Bank's policy meeting and U.S. third-quarter GDP numbers to gauge the developed nations' oil demand outlook.
Brent was down 76 cents at $104.48 a barrel by 0943 GMT. U.S. oil lost 5 cents at $94.75 a barrel.
"A combination of bearish factors is pressuring the price: most importantly, there is overwhelming global supply with additional OPEC capacity expected before the end of the year," Andrey Kryuchenkov of VTB Capital said.
"A stronger dollar isn't helping either."
Gains in the U.S. currency make dollar-denominated crude more expensive for buyers outside the United States and are negative for oil demand.
World powers will seek to hammer out a breakthrough deal with Iran to start resolving a decade-old dispute over its nuclear programme in two-day talks that begin on Thursday.
Although both sides 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 are also awaiting U.S. nonfarm payrolls data on Friday to gauge when the Federal Reserve might begin winding down its $85 billion-a-month bond-buying programme.
A roll-back would boost the dollar, making dollar-denominated assets more expensive for holders of other currencies.
Before that, markets will look to the first reading of U.S. third-quarter GDP later on Thursday. Economists in a Reuters survey forecast a 2.0 percent annualised rate of growth compared with 2.5 percent in the second quarter.
Data on Wednesday showed the euro zone's economic recovery lost a little momentum last month, making the U.S. numbers all the more crucial to gauge the demand outlook. (Additional reporting by Manash Goswami in Singapore; Editing by Dale Hudson)
