Assad is determined to oust rebels from a key southern region bordering Jordan and the Israeli-occupied Golan Heights.
For nearly two weeks, regime forces and their Russian allies have battered rebel-held parts of southern Syria.
Already Russian missiles and Syrian bombs are embracing the countryside south and east of Deraa.
Syrian forces have been battering rebel-held towns in Daraa for nearly a week, leaving at least 29 civilians dead.
Turkish forces and allied Syrian rebels seized the northwest Afrin region from Kurdish fighters in March.
"IS is entrenched in tunnels and underground shelters and has been conducting counter-attacks since May 5," says SOHR.
The bombed centre's rubble yields little proof of being the chemical warfare research centre that it's claimed to be.
The attack appears to have been carried out by Israel, Syrian Observatory for Human Rights says.
“We are not withdrawing,” says the US Defence Secretary terming the operations "an ongoing fight".
Envoy urges world to prevent a fresh humanitarian disaster as officials warn aid funding running “desperately short”.
During a reconnaissance mission “the team came under small arms fire and an explosive was detonated,” says OPCW chief.
Syrian government has provided 15 buses for refugees returning from Shebaa.
Putin and Rouhani agree that the strikes have damaged the chances of achieving a political resolution in the conflict.
A recap of events that began with a suspected gas attack and ended in retaliatory military strikes by the West in Syria.
How could Theresa May follow an American president who the world knows is crackers, insane, chronically unstable?
Syria denounces Western attack as "barbaric", Russia calls for emergency UN session.
British PM Theresa May insists the attacks are not meant to "intervene in a civil war" or "regime change".
US, France and Britain are finalising plans for an expected strike against Syrian President Bashar al-Assad's regime.
“I risked my life to come..I won't leave until I find my home...I want one look even if it's the last," says one woman.
Opponents of unilateral US action call emergency closed-door UN meeting; UK also schedules emergency cabinet meeting.
With renewed US military action seemingly imminent, both Washington and Moscow raised the rhetorical stakes.
Seven soldiers' bodies flown to Tehran for burial after Monday's strike which Syria, Russia and Iran blame Israel for.
Syrian war-monitoring group says 14 people, including Iranians, killed in a missile attack early in the morning.
France initiates the call, followed by the US, Britain, Kuwait, Sweden, Poland, Peru, the Netherlands and Ivory Coast.
"President Putin, Russia and Iran are responsible for backing Animal Assad," tweets US president.
First responders, known as White Helmets, report the attack, say entire families found suffocated in homes and shelters.
“Let the other people take care of it now. Very soon, very soon, we’re coming out."
Government forces hold 90 per cent area of Ghouta.
About 7,000 people would depart in the deal starting on Saturday morning, including fighters carrying light weapons.
The evacuation will likely pressure rebel groups in the remaining two pockets of Ghouta to accept similar deals.