* Kuwait says it supports Saudi/Russian push to extend curbs
* Rising supplies elsewhere undermine cuts
* U.S. output up 10 pct since mid-2016 to 9.3 million bpd
* Libyan and Nigerian production recovering from disruptions (Updates throughout, changes dateline, previous SINGAPORE)
LONDON, May 16 (Reuters) - Oil prices extended gains on Tuesday after top producers Saudi Arabia, Russia and Kuwait supported prolonging supply cuts until the end of March 2018 in a bid to drain a global glut.
Brent crude oil was up 30 cents at $52.12 a barrel by 0750 GMT. U.S. light crude was 25 cents higher at $49.10 a barrel. Both benchmarks have risen more than $5 a barrel since hitting five-month lows 10 days ago.
Saudi Arabia and Russia said on Monday they agreed on the need for a 1.8 million barrels per day (bpd) crude supply cut to be extended for nine months, until the end of March 2018.
Kuwait's oil minister, Essam al-Marzouq, said on Tuesday he supported the Saudi/Russian initiative. Other OPEC states are also expected to back the move at a meeting in Vienna on May 25.
U.S. bank Goldman Sachs said the deal would likely extend the oil price rebound "although the rally so far ... has remained modest compared to the move that occurred last year when the OPEC cuts were first announced."
James Woods, investment analyst at Rivkin Securities, said world oil supplies would likely remain plentiful, even if OPEC extended the production cut as expected.
"As we have seen over the past six months, rising U.S. production and record inventories have kept upside limited and a nine-month extension at this stage is unlikely to break that."
Goldman Sachs said output would increase from OPEC members which were exempt from the cuts. Libya and Nigeria, which have both faced disruptions to production, were both excluded from limits on their output.
In addition, U.S. oil production is rising very quickly and is now up more than 10 percent since mid-2016 to 9.3 million bpd <C-OUT-T-EIA>.
"These combined volumes could largely offset the benefit of the extended cuts," Goldman Sachs said.
Goldman Sachs said it kept its average Brent price forecast for the third quarter of 2017 at $57 per barrel. (Additional reporting by Henning Gloystein in Singapore; Editing by Edmund Blair)