By Jack Stubbs and Ahmed Aboulenein
LONDON (Reuters) - Brent crude oil stabilised around $80 a barrel on Monday as world powers extended talks with Iran over its nuclear programme, maintaining sanctions and preventing an immediate increase in Iranian oil supply to world markets.
The decision came ahead of a key meeting of OPEC to discuss production in response to a collapse in oil prices.
British Foreign Secretary Philip Hammond said the talks between Iran and six world powers had made clear progress and would resume next month. Negotiators had until June to come up with a comprehensive deal.
Brent was trading at $80.00 a barrel, down 36 cents, by 1400 GMT. The contract hit a one-week high of $81.61 on Friday. U.S. crude was also down 36 cents at $76.15.
Oil prices have fallen 30 percent since June, with Brent plunging from a high above $115 and U.S. crude from above $107.
Ministers from the Organization of the Petroleum Exporting Countries meet on Nov. 27 and may decide to cut output.
Iran, alongside fellow OPEC members Libya and Venezuela, has urged fellow crude producers to support oil prices through production cuts ahead of the cartel's meeting.
Fund managers say oil prices could plunge to $60 a barrel if the OPEC fails to make significant cuts to reduce an oversupply on world markets.
"The longer the price stays weak, the more amicable OPEC members will be to follow a collective course of action that involves cutting," said Harry Tchilinguirian, senior oil strategist at French bank BNP Paribas.
"The most likely scenario is that we get a cut of 1 million barrels per day (bpd), maybe a bit more."
In desperate need of higher oil prices to support its economy, Russia made a last ditch attempt to sway the OPEC decision on Monday, suggesting it could cut oil production by around 15 million tonnes a year (300,000 bpd) from next year.
Russian Energy Minister Alexander Novak said on Monday there was a possibility of an OPEC output cut but "it is not high".
A cut in Chinese interest rates on Friday helped bolster oil prices, raising expectations that demand could be stimulated in the world's biggest energy market.
Asian markets rallied on Monday with shares in Shanghai hitting three-year highs as the prospect of further policy stimulus in China and Europe whetted risk appetites globally while sending the euro skidding.
(Additional reporting by Henning Gloystein in Singapore; Editing by Christopher Johnson)
