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.

Russia and Turkey, at loggerheads since Ankara shot down a Russian warplane last week, have suspended talks on their joint TurkStream project to pipe gas to Turkey and southern Europe, Russia's energy minister said Thursday.

"Currently talks are suspended," Energy Minister Alexander Novak said, quoted by RIA Novosti state news agency.

The euro tumbled against the dollar Thursday as dealers bet on fresh stimulus from the European Central Bank later in the day, while most Asian stock markets fell following the previous day's gains.

Asian energy firms tracked losses in their U.S. counterparts as a supply glut and strong dollar weigh on oil prices ahead of a key meeting of the OPEC oil cartel.