A power blackout hit most of the energy-rich Gulf state of Kuwait Wednesday, disrupting traffic and a number of vital facilities but without affecting oil installations.

The electricity and water ministry said a technical problem at one of the country's five power plants forced it to cut power as a precautionary measure to protect the network, according the KUNA news agency.

Low oil prices normally help grease the wheels of business and spur global economic growth, but Moody's said Wednesday it would not revise its forecasts for the G20, citing a variety of offsets to the expected windfalls.

"For the G20 economies, we expect GDP growth of just under 3.0 percent each year in 2015 and 2016, unchanged from 2014 and from our November 2014 Global Macro Outlook," the credit ratings agency said in its latest outlook report.

Oil prices rebounded in Asia on Wednesday following a sharp decline in the previous session, analysts said, as investors await a weekly U.S. stockpiles report later in the day.

U.S. benchmark West Texas Intermediate (WTI) for March delivery rose 44 cents to $50.46 a barrel while Brent crude for March rose 16 cents to $56.59 in afternoon trade.

The euro rose in Asia Wednesday, with investors awaiting talks between Greece and its creditors over renegotiating a bailout deal, while the dollar firmed against the yen on expectations the Federal Reserve will hike interest rates.

The euro bought $1.1318 and 135.31 yen in afternoon Singapore trade, against $1.1315 and 135.15 yen in New York late Tuesday, while the greenback rose to 119.55 yen from 119.44 yen.

Kiev has requested a restructuring of its debt to Russia but Moscow is expecting its $3 billion loan to be repaid in full this year, Russia's finance minister said Tuesday.

"Ukraine asked us to review the issue of restructuring its debt," Finance Minister Anton Siluanov told Russian media on the sidelines of the G20 summit of finance ministers and central bank chiefs in Istanbul.

Standard and Poor's has lowered the outlook for the world's top oil exporter Saudi Arabia to negative and downgraded its Gulf partners Oman and Bahrain on sliding oil prices. 

But despite the large budget deficit planned by Riyadh for this year, the agency maintained its sovereign credit ratings for the kingdom, as well as neighboring Abu Dhabi and Qatar, citing their "very strong fiscal positions."

Oil prices fell in Asia on Tuesday after the International Energy Agency (IEA) predicted that global oil prices will recover only partially over the next five years, analysts said.

U.S. benchmark West Texas Intermediate (WTI) for March delivery slipped 74 cents to $52.12, while Brent crude for March eased 77 cents to $57.57 in afternoon trade. 

Greece's radical new government on Tuesday was fine-turning details of a controversial reform deal it hopes to seal with skeptical EU creditors at critical talks this week in order to liberate the country from a "toxic" bailout.

At talks kicking off with an emergency meeting of eurozone finance ministers Wednesday, Greece will plead its case for stop-gap financing, with a view to clinching an austerity-free reform deal to run from September 1.

A Russian business lobby group made a push Tuesday for Japanese investment as its economy struggles under Western sanctions linked to its role in the Ukraine crisis.

Even as the United States and Europe delayed another round of measures while they push a peace plan, Moscow is looking for cash to replace money that has fled, hoping to tempt resource-poor Japan with oil and gas.

The former HSBC employee who leaked sensational secret documents alleging the bank helped wealthy customers dodge millions of dollars in taxes warned Tuesday that the revelations are just the "tip of the iceberg".

The files created global shockwaves on Monday, spotlighting the financial dealings of the world's ultra-rich and prompting British lawmakers to launch an inquiry into the London-based bank.