LONDON (Reuters) -- Oil prices were steady above $58 a barrel on Friday after OPEC agreed to curb output by more than expected and some members said the cartel could even cut production again before the end of the year.

Ministers agreed to cut output by 1.2 million barrels per day from Nov. 1, some 200,000 bpd more than anticipated.

The market briefly surged above $59, but gains were later checked by nagging concerns that some OPEC members may fail to comply with the curbs.

U.S. crude rose 12 cents to $58.62 a barrel by 1055 GMT, just $1.50 above the 2006 low touched just a week ago.

London Brent crude fell 2 cents to $60.85 a barrel.

OPEC, which supplies about a third of the world's crude, said in a statement after an emergency meeting in Doha that oversupply had destabilized the oil market.

The cut was its deepest since January 2002 and is equal to about 4.3 percent of September supply.

"It was a surprise. It shows the determination of OPEC," Tetsu Emori, chief strategist at Mitsui Bussan Futures Ltd. in Tokyo, said. "They obviously wanted to send a message to the market."

Some ministers said a further cut of 500,000 bpd could follow when OPEC next meets in Nigeria in December.

They said they were concerned about high fuel stocks in consumer countries, particularly in the United States, and a projected drop in demand for OPEC oil in 2007 as competitors bring more supplies online.

"This is not the end of the road because we have another meeting coming up," Saudi Arabia's Oil Minister Ali Al-Naimi told Reuters.

Naimi gave the full support of the world's largest exporter to the cut, and said that Saudi Arabia had already notified customers of lower supply.

Saudi Arabia will shoulder around 32 percent of the cut, amounting to 380,000 bpd.

Ministers' failure to speak with one voice before the hastily-arranged talks had deepened oil's losses of around 25 percent from a mid-July peak of $78.40 a barrel.

To sidestep the issue of quotas and market share that analysts said had begun to cost the cartel credibility, OPEC published only a list of individual cutbacks but left formal quotas unchanged.

Analysts said OPEC's next task was to prove to the market it really was curbing supplies. "There's still a degree of skepticism over whether they will deliver all the cuts," said Tobin Gorey, commodity strategist at Commonwealth Bank of Australia. "For all the extra barrels the market's put on about 50 cents -- not much."

OPEC's cut also reinforced signals that it would defend a price of about $60 a barrel, high enough to justify its investment in future production capacity but low enough to allow economic growth and deter a flood of alternative fuels.

"The drop in prices that has already occurred has had a remarkably positive influence on consumer attitudes and spending in the U.S.," said Adam Sieminksi of Deutsche Bank. "The shopping season is coming up and it's going to be a lot better with oil at $60 than at $80."

Algerian Energy and Mines Minister Chakib Khelil said a $50-$60 a barrel range for OPEC's basket of crudes -- about $55-$65 a barrel for U.S. futures -- would be acceptable.