OPEC's policy of maintaining high oil production risks heaping more downward pressure on oil prices, especially with Iranian crude set to enter the global marketplace, analysts say.

While lower prices eat into the revenues of the oil cartel's members, cheap crude may result in lower production from non-OPEC nations -- helping countries like Saudi Arabia preserve their market share.

As Spain's flagship renewable energy giant Abengoa teeters on the edge of bankruptcy, concerns are mounting over the fate of thousands of employees and its numerous projects around the world, just weeks ahead of crux general elections.

The group filed for protection from its creditors late last month, giving it four months to find a solution to its astronomical debt or go bankrupt and become Spain's biggest-ever corporate failure.

Portugal's new left-wing, anti-austerity government announced late Friday it was moving to halt the privatization of transport systems in Lisbon and Porto, a measure introduced by its right-wing predecessor.

The government will ask the Court of Auditors to "suspend the authorization approval" which would have greenlit the privatization, it said in a statement carried by the Portuguese news agency Lusa.

With this week's big events finished, Wall Street is beginning to turn its sights back to the Federal Reserve and to the prospects of a "Santa Claus rally."

Next week's calendar is light compared with this week's news deluge, which included a European Central Bank meeting, an OPEC meeting and major public appearances by Federal Reserve Chair Janet Yellen.

U.S. Secretary of State John Kerry on Friday hailed troubled Greece's economic recovery efforts in the midst of a huge migration challenge as he arrived in Athens for a brief visit.

"I appreciate the way you are approaching economic reforms efforts (...) it is not easy," Kerry told Greek Prime Minister Alexis Tsipras.

Volkswagen car sales in Britain dropped by 20 percent in November compared to the same time last year following the company's admission it had cheated on U.S. diesel emissions tests.

The Society of Motor Manufacturers and Traders says there were 12,958 Volkswagen registrations last month in the U.K., compared to 16,196 in November 2014. Volkswagen admitted in September it had installed a device in computer software that allowed it to rig emission tests.

Chinese President Xi Jinping announced $60 billion of assistance and loans for Africa at a summit in Johannesburg on Friday, signalling China's commitment to the continent despite a recent fall in investment.

China's economic growth has taken a dip this year, triggering a global commodities slump and forcing Beijing to slash investment in Africa by more than 40 percent in the first six months of 2015.

OPEC appeared on course to maintain current oil output at a meeting here Friday rather than cut production to lift sagging crude prices.

Despite oil prices plunging by more than 60 percent in 18 months, OPEC kingpin Saudi Arabia and the cartel's other Gulf state members are defying calls to reduce output -- in a year-long strategy of attempting to preserve market share and fend off competition from non-OPEC and world leading producers Russia and the United States.

The German central bank or Bundesbank on Friday said it was upbeat about the outlook for expansion in Europe's biggest economy, upgrading its growth forecast for 2017. 

"The Bundesbank's economists expect Germany's real gross domestic product (GDP) to grow by 1.7 percent this year, followed by a rise of 1.8 percent in 2016 and 1.7 percent in 2017," the central bank said in a statement. 

Iran will not bow to pressure to avoid increasing its oil output following the lifting of sanctions despite slumping crude prices, its oil minister insisted here on Thursday.

"We don't accept any discussion about the increase of Iranian production after lifting the sanctions," Iran's Oil Minister Bijan Zanganeh told reporters on arrival in Vienna which is hosting Friday's meeting of OPEC.