But Nasseri declined to say whether he backed further output cuts to support prices, which he agreed were still low despite compliance by Opec members with 2.6 million barrels per day (bpd) of supply cuts agreed so far this year.

"All options are open," Nasseri said when asked if he believed further cuts were a possibility given that prices have failed to come near the targeted $17 per barrel favoured by some members of the Organisation of the Petroleum Exporting Countries. Benchmark Brent Blend crude oil closed just above $13 a barrel on Friday, down six dollars a barrel on last year's average and close to a 10-year low. Nasseri told a news conference earlier that stabilising prices should be a joint effort between Opec and non-Opec producers, adding thatit was low oil demand and not excess supply that was holding prices down.

"Without Opec compliance with the cuts, we would have seen prices go to seven or eight dollars," he said.

Opec and non-Opec producers agreed this year to take three million bpd out of the market to rescue prices, which Nasseri said might stabilise if the cuts were adhered to and demand in the fourth quarter followed a seasonal trend.

But he said it would be pointless for Opec to shoulder further cuts alone without backing from non-Opec producers. Some producers outside the oil producer cartel have said they do not favour a further cut at this time, among them is Mexico, which alongside Opec heavy weights Saudi Arabia and Venezuela orchestrated this year's output reductions.

"Any further supply cuts should be agreed by all member countries because we are looking for non-Opec to support the idea. I think it would be useless for Opec to reduce production while other producers benefit," Nasseri said.