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Activist Titland from Norway and others hold signs during a protest against the 11th WTO's ministerial conference inside the hotel where the conference is held in Buenos Aires

Activist Petter Titland (3rd L) from Norway and other activists hold signs during a protest against the 11th World Trade Organization's ministerial conference inside the hotel where the conference is held in Buenos Aires, Argentina December 12, 2017. REUTERS/Marcos Brindicci

Explosion, gunman attacks rock Norway

A powerful explosion rocked a government building in central Oslo on Friday