FILE PHOTO: The logo of Goldman Sachs is displayed in their office located in Sydney, Australia, May 18, 2016. REUTERS/David Gray/File Photo

(Reuters) - The outcome of the OPEC meeting in Vienna later this week is uncertain given current crude prices and a lack of consensus on an output cut extension deal, Goldman Sachs said on Monday.

“The absence of such a consensus is due to the uncertainty on the progress of the oil market rebalancing as well as Brent oil prices trading at $63 per barrel,” the bank said in a research note.

“The push for a nine month extension, four months before the cuts end and given an accelerating rebalancing further stands in the face of prior comments that the cuts should remain data dependent to assess their effectiveness.”

U.S. oil prices fell more than 1 percent on Monday, easing from two-year highs on prospects of higher supply from a planned restart of the Keystone crude pipeline and uncertainty about Russia’s resolve to join in extending output cuts ahead of this week’s Organization of the Petroleum Exporting Countries meeting.

On Friday, Russia said it was ready to support extending an output cut deal. Still, Russia has not given a timeline, and on Monday there were signs Russia may find it hard to comply.

Goldman Sachs said despite a less clear outcome, it viewed risks to oil prices as skewed to the downside this week as current prices, timespreads and positioning already reflect the high probability of a nine-month extension.

“We continue to expect a gradual ramp up in OPEC and Russian production from April onward,” Goldman said, adding “as a result, the announcement of an only six month extension would still initially appear bullish relative to our expectation.”