Senior representatives of OPEC and other oil producing nations are meeting in Vienna ahead of a ministerial conference of the oil cartel next month to discuss limiting production.

The previously unannounced meeting Saturday was aimed at hammering out details of an agreement last month to roll back output in hopes of increasing prices.

Six non-OPEC producers, including Russia and Azerbaijan, also have representatives at the meeting.

Last month's meeting set a production target for OPEC's 14 member countries of between 32.5 and 33 million barrels a day, a reduction of less than 1 million-barrels. But the perpetual difficulty is getting agreement from individual members to cut back.

OPEC Secretary General Mohammad Sanusi Barkindo alluded to the problem, saying "it is only together ... that we can move forward."