Oil prices edged lower in Asia on Monday as a rally late last week fizzled out, owing to lingering concerns about weak demand and a global supply glut, analysts said.

U.S. benchmark West Texas Intermediate (WTI) for delivery in February eased 37 cents to $48.32 in afternoon trade and Brent crude for March fell 37 cents to $49.80.

Switzerland's central bank chief on Friday defended the institution's shock decision to scrap efforts to stop the overheated franc rising, insisting the turbulence rocking markets and the Swiss economy should settle.

"You must remember that the currency cap from the beginning was supposed to be an exceptional and temporary measure," Thomas Jordan said in an interview to be published in the Saturday editions of Swiss dailies Le Temps and NZZ.

Moody's cut Russia's credit rating to one step above junk level Friday and warned the country was under review for a further downgrade.

Moody's said that the plunge in oil prices and in the ruble would further erode Russia's economic growth potential and that it had concerns about the government's financial strength.

The euro fell Friday against the dollar on growing expectation that the European Central Bank will launch stimulus next week to jump-start the ailing eurozone economy.

The euro fell below $1.15 for the first time since November 2003, before recovering to trade at $1.1566 around 2200 GMT. Late Thursday the shared European currency traded at $1.1623.

The European Central Bank will introduce quantitative easing next week but in a manner that shares risks among all eurozone nations, following concerns from Germany, the Financial Times reported Saturday.

The ECB holds its first policy meeting of the year on Thursday and is widely expected to announce some sort of program of sovereign bond purchases -- or QE -- to try to kick-start the eurozone's sluggish economy.

Voters gathered around a smartly-dressed candidate from Greece's anti-austerity party Syriza in an affluent Athens suburb asking the question everybody wants answered: Will the country go bust?

But then the Syriza candidate quickly had to field what's proving another tricky question for his party ahead of next week's elections: Do they have a united plan?

Chinese overseas investment surged past $100 billion for the first time last year, official figures showed Friday, but remained below investment into the country.

Overseas direct investment (ODI) rose 14.1 percent to $102.9 billion in 2014, vice commerce minister Zhong Shan said at a briefing, as Chinese firms continued to buy up assets, particularly energy and resources, to power the world's number two economy.

The euro sank almost two percent against the Swiss franc Friday and Asian markets tumbled as traders were left stunned by Switzerland's shock decision to remove its currency cap against the euro.

Oil edged up slightly, meanwhile, after plunging Thursday in reaction to OPEC's announcement that it produced more than its limit of the black gold in December, despite weak demand, low prices and a supply glut.

Oil prices rebounded in Asia Friday after plunging in the previous session in reaction to news that OPEC had overproduced in December, while it also cut its global demand outlook.

U.S. benchmark West Texas Intermediate for February, which dived $2.23 Thursday, was up 22 cents at $46.47.

A New Zealand foreign exchange broker announced it was closing Friday after suffering "a total loss of operating capital" in the wake of Switzerland's shock move to scrap its currency cap.

Global Brokers NZ said the Swiss move resulted in "rare volatility and illiquidity" in the markets.