* OPEC-led supply pact due to expire in March
* Russian minister calls for continued cooperation
* Oil ministers say supply cuts reducing inventories (Adds details from OPEC, non-OPEC meeting in Vienna)
LONDON, Sept 22 (Reuters) - Oil prices were steady on Friday, as investors waited to see whether major producers meeting in Vienna would back an extension to output cuts beyond March next year.
Brent crude futures were up 4 cents at $56.47 a barrel at 1100 GMT.
U.S. West Texas Intermediate (WTI) crude futures were down 2 cents, at $50.53 per barrel.
Some ministers from the Organization of the Petroleum Exporting Countries, Russia and other producers were meeting in Vienna to discuss their deal to cut supplies that runs to March.
Ministers said they would discuss extending the pact, although two OPEC sources said the group was unlikely to make a specific recommendation for an extension at Friday's talks.
"Since our last meeting in July, the oil market has markedly improved," Kuwaiti Oil Minister Essam al-Marzouq said in an opening speech at the meeting he is chairing. "The market is now evidently well on its way towards rebalancing."
Oil prices have gained more than 15 percent in the past three months to trade above $56 a barrel, suggesting the deal is making progress in getting rid of excess supply.
Russian Energy Minister Alexander Novak said OPEC and the other producers needed to continue coordination and work on a strategy from April 2018, adding oil demand was rising at a "high pace."
Nigeria and Libya, which have been exempt from the curbs, were also invited to attend the talks.
Despite the current output restraints increasing U.S. oil production has curbed price gains. Hurricanes in the Gulf of Mexico have also pushed up crude inventories as some U.S. refineries have been shut by flooding.
The Energy Information Administration (EIA) on Wednesday reported that U.S. crude production rose to 9.51 million bpd in the week ended Sept.15 from 8.78 million bpd a week earlier.
Commerzbank said in a note that oil prices were finding some support from tensions sparked by plans the regional government of Iraqi Kurdistan to hold an independence referendum.
Iraq's government and Western powers oppose holding such a vote in the oil producing region.
(Reporting by Fanny Potkin in London and Jane Chung in Seoul; Editing by Greg Mahlich and Edmund Blair)