Six civilians including several children were among 19 people killed Thursday in the fiercest clashes to rock Syria's Daraa province since it was captured by the government, a war monitor said.
Artillery shelling by regime forces on the village of Al-Yadudah, northwest of Daraa city, killed a woman, her child and three other youngsters, said the Britain-based Syrian Observatory for Human Rights.
Regime artillery fire also killed a sixth civilian in the district of Daraa al-Balad further south, according to the Observatory.
The deaths bring the toll for Thursday's clashes to a total of 19 across the province, which is located in southern Syria.
The figure includes at least eight Syrian regime fighters and five gunmen affiliated with former opposition groups, the monitor said.
Syrian army and allied forces recaptured Daraa from rebels in 2018, a symbolic blow to the anti-government uprising born there in 2011.
State institutions have returned but the army still has not deployed across the whole province, and tit-for-tat bombings and assassinations between former opposition figures and regime forces have since become routine.
Tensions flared on Thursday, leading to what the Observatory called the "most violent and broadest clashes in Daraa since it came under regime control".
Fighting started when regime forces fired artillery shells towards the former opposition hub of Daraa al-Balad in tandem with a ground push, the Observatory said.
In response, gunmen launched a counterattack across many parts of the Daraa countryside, where they seized several regime positions and captured more than 40 regime fighters, according to the Observatory.
Both sides have since upped artillery attacks.
Citing a medical official in a regime-held part of Daraa city, the official SANA news agency said mortar attacks by armed groups on Thursday killed two civilians, including a child.
Many former rebels stayed in Daraa instead of evacuating under a Moscow-brokered deal, either joining the army or remaining in control of parts of the province.
Daraa al-Balad, a southern district of Daraa city, is among the areas controlled by former opposition forces.
The pro-government Al-Watan newspaper on Thursday said the Syrian army had started "a military operation against hideouts of terrorists who thwarted a reconciliation deal".
SANA said that the "Syrian army has deployed in several areas neighbouring Daraa al-Balad to tighten security", accusing local fighters there of carrying out attacks against soldiers and civilians.
In March, gunmen in Daraa killed 21 Syrian soldiers in a bus ambush.
The soldiers were en route to Al-Mzairib district in the rural west of the province to arrest a former opposition commander when they came under fire.
The war in Syria has killed nearly 500,000 people and displaced millions since it started in 2011.