Oil Prices Tumble as Talks Stall Over Output Limits : OPEC: Members agree oil flow must be reduced to bolster shaky prices, but no one wants to make the first or deepest cut.

VIENNA, Austria —  OPEC talks appeared near deadlock Thursday and oil prices tumbled as the cartel struggled to reconcile competing demands to sell more oil within an output ceiling low enough to push prices higher.

“I’m not sure the 13 members will join the agreement,” said one senior oil minister, attending a twice-yearly conference here of the Organization of Petroleum Exporting Countries.

Dissension is so great that some ministers were unsure whether any eventual deal setting new production levels would be supported by all members of OPEC.

World oil prices, already down 10% since mid-October on fears of excess OPEC production, plunged to a seven-month low as traders feared that the group would fail to produce a credible deal and continue to pump at will.

January prices for the international benchmark, North Sea Brent crude, fell 43 cents to $18.75 per barrel as ministers said the group still had many differences as they emerged from an afternoon meeting.

Algerian Oil Minister Hacene Mefti told reporters that a full agreement was unlikely later Thursday. Asked if OPEC was having problems setting a total output ceiling or individual member shares, Mefti said: “Both.”

The producer group has formed a small committee to present three options for a possible output deal, OPEC President Alirio Parra said.

Iran and Nigeria are pressing for higher sales, while OPEC heavyweight Saudi Arabia, the world’s largest producer, is reportedly reluctant to cut output.