Hopes for a peace plan brokered by the United Nations through envoy Kofi Annan showed signs of crumbling, with the Syrian government making a failed demand that the rebels give a written guarantee of a ceasefire on the eve of the withdrawal deadline. Fifty-nine more people were reported killed in violence Sunday. Meanwhile, more than 100 people, the majority of them civilians, have been executed by Syrian troops over the past four months, said the international rights organization Human Rights Watch. And that number could be low, as the group only included cases backed up by witnesses. Reports of other executions of civilians were not uncommon in the country where troops have implemented draconian measures to put down a more-than-yearlong uprising against President Bashar al-Assad.