* OPEC, non-OPEC ministers meeting in Russia on Monday
* Market looking for clues on outlook for Nigeria, Libya output
* OPEC Sec General says oil market rebalancing to speed up in H2 (Updates prices)
TOKYO, July 24 (Reuters) - Oil prices inched up but held near a one-week low on Monday ahead of a joint OPEC and non-OPEC meeting later in the day that may address rising output in Nigeria and Libya.
London Brent crude for September delivery was up 12 cents at $48.18 a barrel by 0651 GMT. The contract settled down $1.24, or 2.5 percent, on Friday after a consultancy forecast a rise in OPEC production for July.
NYMEX crude for September delivery was up 7 cents at $45.84 a barrel.
Ministers from the Organization of the Petroleum Exporting Countries (OPEC) and other non-OPEC producers will meet in the Russian city of St Petersburg on Monday to review market conditions and examine any proposals related to their pact to cut output.
Sources familiar with the talks said the meeting may recommend a conditional cap on production from Nigeria and Libya - two OPEC members so far exempt from output cuts - although some analysts were deeply sceptical the group would make such a move.
"Output cuts by Libya and Nigeria would be next to impossible considering Libya was just re-emerging from the civil war, for example," said Kaname Gokon, strategist for commodities brokerage Okato Shoji in Tokyo.
OPEC and some non-OPEC states including Russia agreed last year to cut production by 1.8 million barrels per day (bpd) in a deal that has been extended to March 2018.
Russian Energy Minister Alexander Novak said Libya and Nigeria should cap output when their output stabilizes, the Financial Times reported.
Kuwait's oil minister, Essam al-Marzouq, said on Saturday that compliance was good with oil production cuts by OPEC and non-OPEC countries and that deeper curbs were possible.
Meanwhile, OPEC Secretary General Mohammad Barkindo said on Sunday that a rebalancing of the oil market is progressing more slowly than expected, but will speed up in the second half of 2017.
"Oil looks likely to remain stuck in a tight range, as investors await any signs that OPEC will intensify its effort to rebalance the market," ANZ bank said.
The United States is considering financial sanctions on Venezuela that would halt dollar payments for the country's oil, sources told Reuters, which could severely restrict the OPEC nation's crude exports.
The International Monetary Fund on Monday kept its growth forecasts for the world economy unchanged for this year and next, although it slightly revised up growth expectations for the eurozone and China.
(Reporting by Osamu Tsukimori; Editing by Joseph Radford and Richard Pullin)