DAMASCUS - Ongoing clashes in suburbs of Syrian capital Damascus and other hotspots nationwide between the government troops and armed rebels marked the second anniversary of the Syrian conflict on Friday.

The Britain-based Syrian Observatory for Human Rights said as many as 18 civilians were killed Friday due to the government troops' bombardment on Damascus' suburbs of Muadamieh, Douma, Hammourieh, Saqba and the resort town of Zabadani.

In the northern province of Aleppo, the al-Qaida-linked Nusra Front, backed by other radical groups, managed to storm the Armament Battalion in the Khan Touman town after intense clashes that have been raging on in the area since Thursday evening, the observatory said, adding that truckloads of ammunition have been taken away by the assailants from the seized depots.

The clashes have killed 18 soldiers and 14 fighters from al- Nusra, the observatory said.

Meanwhile, the state-run SANA news agency said "terrorists" attacked with mortar rounds the residential areas and worship places in al-Sulaimanieh neighborhood in Aleppo city, causing material damage but no casualties were reported.

An official source told SANA that a mortar round fell near the Syriac Orthodox Church and caused material damage in the place, adding that another mortar shell slammed into al-Maarri school in al-Sulaimanieh and caused property losses.

The state news agency also reported government troops' operations in many restive areas across the country.

The Syrian crisis has started in mid-March 2011. The crisis has begun with peaceful protests demanding reforms and freedoms and quickly evolved into an armed insurgency. The UN says that more than 70,000 people have been killed and millions of others were displaced internally and externally during the two-year-old crisis.