Russia and Kazakhstan, both members of the broader and informal group known as OPEC+, said they had not yet agreed to a deeper cut
The Wall Street Journal also reported on Thursday that China had invited top U.S. trade negotiators for a new round of talks in Beijing, citing unnamed sources.
International benchmark Brent crude futures, were at $57.61 a barrel by 0009 GMT, up 23 cents, or 0.4%, from their previous settlement
The current version of the deal by the so-called Opec+ coalition calls for production cuts of 1.2 million barrels a day
Opec along with major non-Opec producers such as Russia have pledged to reduce their oil production to cut into a supply glut
OPEC said demand for its crude would fall to 30.59 million barrels per day, 240,000 bpd less than predicted last month
US sanctions on Venezuela will limit oil transactions between Venezuela and other countries and are similar to those imposed on Iran last year
The reduction in December means that should OPEC fully implement the new January 1 cut, it will avoid a surplus that could weaken prices
The oil cartel has decided to cut production by close to 1.2 million barrels per day (mbpd) following a drop in international crude oil prices in the last one month
Crude surged as much as 5.4% in London, raising the risk that the deal could anger US President Trump, who had urged the group to keep the taps open and prices low
Opec failed to agree on concrete parameters for a deal to restrict output on Thursday
Below is a round-up of each country's position and an assessment of its likely willingness to make further cuts for next year
If the group doesn't alter its current track, global oil stockpiles are set to rise by around 1.8 mn barrels a day in the first quarter of 2019 and to continue building throughout the year
The UAE holds the presidency of the 14-nation Organization of the Petroleum Exporting Countries in 2018
Under the current deal, OPEC, Russia and other producers are cutting supply by about 1.8 million bpd in an effort to drain global inventories and boost oil prices.
Two OPEC delegates told Reuters the group had agreed to extend the cuts by nine months until the end of 2018, as largely anticipated by the market.