* Weekly U.S. crude stocks rise 4.5 mln barrels - API

* U.S. government oil inventory data due at 1430 GMT

* Iraq not yet reached full oil market share - PM

(Updates throughout, changes dateline, previous SINGAPORE)

By Karolin Schaps

LONDON, Aug 24 (Reuters) - Brent oil fell 1.5 percent on Wednesday on an unexpected increase in U.S. crude stocks that revived worries about the supply glut that has capped prices for the past two years.

Global benchmark Brent crude was down 74 cents at $49.22 a barrel at 0809 GMT, after touching an intraday low of $49.07.

U.S. West Texas Intermediate (WTI) crude was down 86 cents, or 1.8 percent, at $47.24 a barrel. Earlier in the session, the contract came close to shedding a dollar at $47.13.

"API (data) showed a big build last week and that supported the quick turnaround in sentiment," said Ole Hansen, Saxo Bank's head of commodities research.

Industry data from the American Petroleum Institute (API) showed on Tuesday that U.S. crude inventories had risen by 4.5 million barrels in the week ending Aug. 19.

Analysts had expected a 455,000-barrel fall.

The U.S. government will publish its own weekly crude stocks data at 1430 GMT on Wednesday.

Brent briefly spiked above $50 in the previous session after Reuters reported Iran was sending positive signals that the country may support joint OPEC action to prop up oil prices.

But analysts and traders remain sceptical that producers will come to an agreement at a meeting in Algeria scheduled for Sept. 26-28 as various OPEC members have their own agendas.

Iraq's prime minister said on Tuesday his country had not yet reached its full oil market share, suggesting the government would not restrain crude output as part of any OPEC agreement.

"I really can't see the sense for Saudi, in particular, to actually have some meaningful constraint on production because there is quite a lot of capacity of U.S. shale to come on quite quickly," said Ric Spooner, chief market analyst at CMC Markets.

He said he could see prices drifting closer to $45 a barrel over the next few days.

(Additional reporting by Mark Tay in Singapore; Editing by Dale Hudson) ((karolin.schaps@thomsonreuters.com)(+44)(0)(207 542 6622)(Reuters Messaging: karolin.schaps.reuters.com@reuters.net))