VIENNA (AP) — OPEC member states are meeting with Russia and other non-OPEC countries in Vienna for talks about a reduction in oil production.

Secretary General Mohammed Barkindo said the discussions began Saturday in a "positive atmosphere" at the headquarters of the oil producers' cartel.

OPEC agreed on Nov. 30 to cut 1.2 million barrels in daily output by its own members in an attempt to raise oil prices that have put pressure on government finances in oil-producing countries including Saudi Arabia.

Now it is hoping for another 600,000 barrels to be cut by countries outside the group.

Barkindo expressed optimism about getting agreement on the 600,000 "or even more maybe."

Much of that is expected to come from major producer Russia, which Barkindo said was co-chairing the meeting.

Russian energy minister Alexander Novak said the meeting was "a unique window of opportunity for oil producers to help the market find an equilibrium. And missing this chance would just be wrong."

Crude prices have risen since the OPEC agreement was announced, with U.S. crude up 1.3 percent on Friday at $51.48 a barrel, 6 percent higher than before the OPEC announcement.

That's despite doubts about how much impact any OPEC-led cutback will have due to weak demand from a sluggish global economy and due to a tendency among some members to produce more than agreed.