OPEC exporters have deferred action on new output curbs - aimed at lifting oil prices - because of growing frustration over a lack of cooperation from its main non-OPEC rival Russia.
OPEC has reached an agreement to reduce oil output by 1.5 million barrels a day from January 1. But implementation of the deal is conditional on a 500,000 bpd cut from rival non-OPEC suppliers.
Iranian Oil Minister Bijan Zanganeh told reporters after a four-hour meeting there was agreement to cut - but conditional on an improved offer from other producers that also include Mexico and Norway.
Oil prices, down from $27.45 since September 11, subsided another 7% this afternoon, with London Brent losing $1.58 at $19.23 a barrel, just above two-year lows.
