The head of the Arab League has asked the U.N. Security Council to boost the size of a U.N. mission in Syria and give it expanded powers to protect people following a surge in violence there, according to a letter leaked to media outlets on Friday. Images of the bloodied bodies of children and others massacred in the city of Houla in attacks blamed on President Bashar al-Assad's forces have shocked the world and highlighted the failure of a 6-week-old U.N.-backed ceasefire plan to stop the violence in the 14-month uprising against Assad's rule. Nabil Elaraby, secretary-general of the Arab...