Syrian forces pounded the battered city of Homs with tank and mortar fire and troops pummelled several rebel strongholds in the north on Saturday,leaving at least 24 dead,opposition activists said. At least 10 people were killed by explosions and sniper fire in Homs,the epicentre of the revolt against the regime of Bashar al-Assad,said activists who accused the forces of shelling residential areas indiscriminately. The shelling started like it does every morning,for no reason. They are using mortar and tank fire, an activist in Homs told Reuters by Skype. He said most residents in the area had fled to safer districts and many were trying to escape the city altogether. Syrian troops have repeatedly targeted Homs,Syrias third largest city,and said last month they had regained the one-time rebel bastion. However,a sharp upswing in violence this past week suggests they are struggling to maintain control. However,the Homs activist,who declined to be named for fear of reprisals,suggested the opposition Free Syrian Army was also incapable of re-establishing their authority. We only have a few rebels here left,there is nothing they can do, he added. Independent verification of the reports is impossible as the authorities have barred access to foreign journalists and human rights workers. Further to the north,security forces killed at least one person and wounded dozens in raids on Saraqib,in Idlib province bordering Turkey,according to the British-based Syrian Observatory for Human Rights,which has a network of contacts in Syria. There are dozens of tanks and armoured vehicles storming Saraqib now and there is heavy artillery fire, an activist called Manhal said via Skype. A portion of the rebels have made a strategic retreat,but there are rebel forces still inside,and about a third of residents have fled the town,he added. Mortars and heavy artillery fire hit also the city of Qusair,in Homs province,reportedly killing three civilians. In the southern province of Deraa,birthplace of the revolt,the activists said a man was shot dead at a checkpoint in an area where a soldier had been gunned down. Three other soldiers were killed in an attack in the northeastern province of Hasaka,it said.