At least 24 persons were killed on Saturday in bombings and an explosion in Syria.Nineteen people were killed in bombings carried out by an unidentified aircraft in Aleppo city, while five others were killed in an explosion in Manbech city, Efe news quoted the Syrian Observatory for Human Rights as saying.The escalation of violence in the province of Aleppo coincided with a ceasefire which started on July 6 and was extended on Tuesday by the Syrian army for 72 hours.