The Syrian army on Saturday declared that the troublesome district of al-Tadamun in the southern part of the capital Damascus "insurgent-free," according to state-run SANA news agency.

Al-Tadamun was the first district in the capital to have witnessed armed insurgency over the past two weeks.

After storming the area Saturday, the Syrian army dug up a mass grave with the bodies of 20 people between al-Tadamun and Yalda area, a Syrian officer told Xinhua.

While al-Tadamun was cleared, clashes continued elsewhere in Damascus, including in Rukn Eddien, Salhieh and Muhajireen.

Meanwhile, SANA said a large number of foreign and Arab fighters have been either killed or rounded up Saturday in northern Aleppo province.

Syria has for long said that a third party has joined the battles in Syria, adding that foreign intelligence and Arab extremists have become part of the cycle of violence.