Twenty-four countries decided to maintain production cut of about 1.8 million barrels per day until December 31, 2018
Speculation mounts that supply curbs by members of the Opec and its allies will be prolonged
OPEC officials have said exports have become a key metric tracked by the market
Non-OPEC compliance, however, has so far been modest
Investors also worried that the rising US oil supply might offset any reductions,
Move follows Russia's optimism about non-Opec producers fully joining Opec's output limits on Saturday in the first such move since 2001
Iraq, along with Iran, had earlier been reluctant to go along with cuts, creating an obstacle for the Opec deal
This follows a $850 billion loss in value last year and $720 billion in 2014
Energy Minister Khalid Al-Falih said Sunday the oil market would recover in 2017 even without cuts
Iran, Iraq and Indonesia had expressed reservations about their level of participation in what would be the group's first supply-limiting deal since 2008
Russia on Wednesday said it was ready to support OPEC's decision on an oil output freeze
Prices rise nearly 3 per cent, extending rally on optimism over first output cut plan in eight years
Oil futures retreated on Thursday as the market grew more sceptical on how OPEC would implement its plan