Global benchmark Brent crude was up $1.41 at $52.25 a barrel by 3.28pm GMT, having touched $52.63, the highest since April 21.
However, the USA is not included and its high output could undermine efforts.
Longer cuts at already agreed-upon volumes are needed to reduce global inventories to the five-year average, the energy ministers of the world's biggest crude producers said at a joint press briefing in Beijing on Monday.
"We've come to conclusion that the agreement needs to be extended".
According to the official Kuwait News Agency, known also as KUNA, Oil Minister Essam al-Marzouq "affirmed full support of the joint position" taken by Saudi Arabia and Russian Federation to extend the agreement to March 31.
Both contracts slid during the session to the lowest since November 30, the day OPEC agreed to cut supply.
A central part of their problem is the USA shale oil business and the competition to the established industry it has come to represent in the past decade.More news: Hacking group offers subscription for NSA code
"Saudi Arabia seems very determined to push oil prices higher by making this joint statement now", said Mr Oystein Berentsen, managing director of oil trading company Strong Petroleum. OPEC ministers plan to meet on May 25 to decide whether to extend cuts in their production beyond June. Butterfill doesn't consider that oil stock would be able to sustain the current rates for a longer time due to the ability of the shale producers to produce shale oil more than that of oil. Prices now are about the same level as when they did the deal. But it is good news for their rivals in the US.
Goldman Sachs said output would increase from OPEC members that were exempt from the cuts.
There's still concern that a surge in USA production, together with an increase in Libyan output and signs of recovery in Nigeria, may undercut the Organization of Petroleum Exporting Countries' strategy to stabilize the market and prop up prices.
USA drilling activity last week rose to its highest in two years, while US production has jumped more than 10 percent since its mid-2016 trough.
"Saudi Arabia and Russian Federation are clearly working closely together". Beyond the element of surprise from today's announcement, and the need for broader ratification by other participants, we believe that such a moderate oil price response is consistent with.
However, last year Saudi officials agreed to the first cut in production for eight years.