IS aimed to cut route between airport and city, but government's counter-attack stopped militants
The Islamic State (IS) group on Saturday launched one of its fiercest assaults yet on the besieged Syrian city of Deir Ezzor, leaving more than 30 government fighters and militants dead.
The brutal attack - on a day that saw many outbreaks of violence across Syria - came as the political opposition said it "supported" forthcoming peace talks in the Kazakh capital Astana.
Unleashing a wave of suicide attacks, rockets, and tunnel bombs, IS killed at least 12 government forces and two civilians in Deir Ezzor, according to the Syrian Observatory for Human Rights.
— AFP news agency (@AFP) January 14, 2017
Syrian government warplanes hit back against IS positions, the Observatory and state media said.
The British-based monitoring group said 20 militants were killed in fierce air raids by Syrian and allied warplanes on the city, where about 200,000 people have lived under IS siege since early 2015.
Syrian state news agency SANA said the army was repelling attacks by IS along several frontlines, including around the military airport controlled by the government.
IS has sought to overrun the entire city, including the key nearby military airport.
Observatory head Rami Abdel Rahman said the attack was the "most violent" assault mounted by IS on the city in more than a year.
"Daesh is amassing its forces to attack Deir Ezzor and breach government lines," a Syrian military source told AFP, using the Arabic acronym for IS.
He said militants had aimed to cut the route between the airport and the city, but that the government's counter-attack had stopped IS.
Violence in Idlib, Damascus
The ceasefire deal appeared increasingly strained on Saturday, with outbreaks of violence in northwest Syria and near the capital.
Fresh raids in the town of Maarat Masrin in the northwest province of Idlib killed eight people, most of them civilians, the Observatory said.
On Friday, three civilians - including a child - were killed in strikes on the nearby town of Orum al-Joz, Abdel Rahman said.
Idlib province is controlled by a rebel alliance led by Fateh al-Sham Front, which changed its name from al-Nusra Front after breaking ties with al-Qaeda last year.
Like IS, Fateh al-Sham is excluded from the truce deal.
New clashes also broke out in Wadi Barada - the main source of water for Damascus.
Water supplies from the area to 5.5 million people in the capital and its outskirts have been cut since 22 December because of fighting.
Rebels and government troops had reached a local agreement on Friday so that water access could be restored, but the Observatory reported a resumption of violence on Saturday.
"Regime forces and Hezbollah violated the agreement" by battering a town in Wadi Barada with rocket fire, Abdel Rahman told AFP.
State news agency SANA on Saturday said that the government's chief negotiator in Wadi Barada, Ahmad al-Ghadban, was killed when "terrorists opened fire... after a meeting".
The Observatory confirmed Ghadban's death.