The U.N. envoy to Syria said Thursday that the besieged city of Homs had become a "theater of death and destruction," urging both sides in the country's civil war to return to negotiations. Lakhdar Brahimi said in a statement that the Syrian government and opposition should resume talks that broke off in February. The central city has seen some of the worst fighting in the 3-year-old conflict. An agreement on a weeklong cease-fire that allowed more than 1,000 civilians to leave Homs' rebel-held areas was hailed as the only achievement of the recent Geneva peace talks that Brahimi mediated. The deal did not hold, however, and fighting between President Bashar al-Assad's forces and the rebels trying to overthrow him has raged for weeks in Homs.