Intense clashes broke out in Syria's Daraa on Monday between government forces and insurgents with both sides shelling parts of the southern city that has been declared a safe zone under a recent Russia-sponsored deal, opposition activists and state media said.
Daraa, the site where Syria's crisis began in March 2011 with anti-government protests, is one of four "de-escalation zones" announced earlier this month during cease-fire talks in Astana, Kazakhstan.
Russia, Iran and Turkey agreed to establish the zones in Syria, signing on to a Russian plan under which President Bashar Assad's air force would halt flights over designated areas across the war-torn country.
Violence had been reported in the "de-escalation zones" since the deal was struck but Monday's clashes were among the worst.
The Britain-based Syrian Observatory for Human Rights said government forces fired 11 missiles on rebel-held parts of Daraa as insurgents, including members of the al-Qaida-linked Levant Liberation Committees shelled government-held parts of the city.
Daraa-based opposition activist Ahmad al-Masalmeh said insurgents repelled a government attack on the city's Manshiyeh neighborhood adding that troops fired as many as 20 missiles on the city.
State news agency SANA said the shelling of government-held parts of the city wounded two women and a child. It added that the Syrian government respects the Astana deal but has vowed to retaliate to any violation.
The violence came as U.S.-backed Syrian fighters marched closer toward the northern city of Raqqa, the de facto capital of the Islamic State group. The Kurdish-led Syrian Democratic Forces has been the most effective group fighting IS extremists in Syria who have lost wide areas around Raqqa over the past months.
The Kurdish-led forces and the Observatory said the U.S.-backed fighters captured the village of Salhabiyeh, west of Raqqa.
In the eastern city of Deir el-Zour, which is contested between IS and the Syrian government, airstrikes targeted several neighborhoods held by IS killing and wounded dozens.
Omar Abu Laila, a Europe-based opposition activist from Deir el-Zour, said the airstrikes were likely carried out by Russian warplanes, adding that seven people were killed and more than 20 wounded. The Observatory said 10 people were killed, including three IS members.
Earlier Monday, IS claimed responsibility for a suicide attack in northwest Syria that killed at least 14 insurgents. The extremists said in a statement that the attack against Ahrar al-Sham fighters was carried out by one of its members who parked his booby trapped motorcycle outside the group's office and detonated it along with an explosive belt he was wearing.
Ahrar al-Sham had blamed IS for Sunday's attack in the village of Tal Touqan in Idlib province. Ahrar al-Sham said the attacker blew himself and his motorcycle up amid the fighters, killing and wounding dozens.