of people killed in unrest in Syria since mid-March has reached at least 2,600 , the U.N. Office of the High Commissioner for Human Rights said Monday . The U.S. State Department , meanwhile , is condemning the killing of a key Syrian opposition organizer who it says died while in the custody of Syria 's security forces . Ghiyath Mattar , described as a key organizer of protests against al-Assad 's regime , was killed after being arrested last Tuesday in the Damascus suburb of Darya , State Department spokeswoman Victoria Nuland said in a statement released Sunday . `` His brave commitment to confronting the regime 's despicable violence with peaceful protest serves as an example for the Syrian people and for all those who suffer under the yoke of oppression , '' the statement said Mattar was arrested along with leading opposition activist Yahya Sharbaji and a number of other activists , Nuland said . Mattar was `` a symbol of what the Syrian revolution should be -- peaceful and nonviolent , '' said one of Mattar 's friends . `` His death is an attack by the regime on peace . His attack is saying ,
-LRB- CNN -RRB- -- At least 26 people were killed Monday in the Syrian government 's ongoing crackdown on dissidents , the pro-democracy group Local Coordination Committees of Syria said . Among the dead was a 12-year-old boy shot to death when Syrian security forces fired on a funeral procession , according to the London-based Syrian Observatory for Human Rights . . The funeral procession was for a protester killed Sunday , the observatory said . In addition , 17 people were killed during operations by the military and security forces in Hama as authorities searched for wanted activists and demonstrators , the organization said . Meanwhile , an adviser to Syrian President Bashar al-Assad said parliamentary elections could be held in the country by the end of the year , Russian media reported earlier Monday . Bouthaina Shaaban , the political and media adviser to al-Assad , was in Moscow on Monday to speak to journalists on the situation in Syria . `` I can tentatively say that such elections may be held either at the end of this year or the beginning of next , '' Shaaban said , according to the RIA-Novosti news agency . The number