After Deadly US Strikes, Syria Beats Back ISIS Assad regime regains territory lost to militants in Saturdays airstrikes By Newser Editors and Wire Services Posted Sep 18, 2016 7:34 AM CDT 27 comments Comments This file photo shows fighters from the Islamic State firing weapons toward Syrian troops and pro-government gunmen, in Deir el-Zour province, Syria. (Militant photo via AP) (Newser) – Syrian government warplanes and special forces on Sunday destroyed several positions of ISIS in the eastern province of Deir el-Zour. The advance regained territory lost Saturday when Syrian troops were accidentally hit with airstrikes by the US-led coalition, reports the AP. The incident has threatened an already-fragile US and Russian-brokered ceasefire that has largely held despite dozens of alleged violations on both sides. The Syrian Foreign Ministry called the strikes a "dangerous and blatant aggression." The ministry's statement, sent to the presidents of the United Nations and the UN Security Council, said US warplanes repeatedly attacked Syrian army positions Saturday in strikes that were "on purpose and planned in advance," and killed dozens of soldiers. Russia's military said at least 62 soldiers were killed in the Deir el-Zour air raid and more than 100 wounded. On Sunday, the state-run SANA news agency quoted an unnamed military official as saying that dozens of ISIS fighters were killed in the offensive on Tharda mountain under cover of Syrian airstrikes; ISIS had claimed its fighters captured Tharda mountain. The Syrian military official said government troops had regained control of areas the extremists captured, "as a result of the American aircraft aggression." Meanwhile, the Syrian Observatory for Human Rights said ISIS fighters shot down a Syrian warplane over Tharda mountain, adding that its pilot was killed. The Observatory said intense strikes by Russian warplanes have killed at least 38 ISIS fighters since Saturday.