Heavy Syrian bombardment killed 44 civilians in rebel-held Eastern Ghouta today, as regime forces appeared to prepare for an imminent ground assault.
The escalation came as pro-government forces were expected to enter the northern Kurdish-controlled enclave of Afrin, to take a stand against a month-old Turkish assault there.
A barrage of air strikes, rocket fire, and artillery slammed into several towns across Eastern Ghouta on Monday, killing 44 civilians and wounding dozens more.
The Britain-based Syrian Observatory for Human Rights said 20 were killed in air strikes on Hammuriyeh and nine others in bombardment on Saqba.
The rest were killed when other areas were pounded. Four children were among the dead.
Residents of Hammuriyeh could be seen rushing inside in a panic as soon as they heard the sound of airplanes.
Alaa al-Din, a 23-year-old Syrian in Hammuriyeh, said civilians were afraid of a potential government offensive.
"Ghoutas fate is unknown. Weve got nothing but Gods mercy and hiding out in our basements," he told AFP on Monday.
"Theres no alternative."
Shelling also hit the town of Douma, where an AFP correspondent saw five toddlers brought to a hospital, covered in dust and wailing uncontrollably.
Medics offered them biscuits to calm them down, to no avail.
Eastern Ghouta is held by two main Islamist factions, but jihadists control small pockets including one directly adjacent to the capital.
But escalating military pressure indicate that the regime would opt for a ground assault instead of talks, the monitor said.
Government troops carried out a relentless five-day bombing campaign earlier this month that killed around 250 civilians in the enclave and wounded hundreds.
Around the same time, the monitor said, the regime began dispatching military reinforcements to Eastern Ghouta.
After days of relative calm, the government sent more than 260 rockets sailing onto Eastern Ghouta on Sunday.
Those rockets, as well as artillery fire and air strikes, killed 17 civilians, said the Observatory.
The regime is keen to regain control of Eastern Ghouta to halt the deadly salvo of rockets and mortars that rebels fire on Damascus.
About half a dozen rockets hit the capital Sunday night, AFP correspondents said. State news agency SANA reported that one person was killed.
More than 20 civilians have been killed by rebel fire this month alone in regime-held Damascus.
All was quiet in the capital on Monday but since rumours of an imminent assault on Eastern Ghouta started spreading, people living close to the rebel enclave started packing their bags.
Jawad al-Obros, 30, said he was looking to move to a hotel in the western sector of the city to escape his home in an east Damascus neighbourhood that has been regularly hit by rockets from Ghouta.
"Were tired of this situation. It seems that theres no solution but a full-blown military one," he told AFP.
More than 340,000 people have been killed since Syrias conflict erupted in 2011 with protests against Assads government.
It has since evolved into a war that has carved up the country into rival zones of influence among the regime, rebels, jihadists, and Kurdish forces.
The Kurdish Peoples Protection Units (YPG) control the northwestern region of Afrin, target of a month-old assault by the Turkish army and allied Syrian rebels.
The YPG has controlled Afrin since 2012, when Syrian troops withdrew from it and other Kurdish-majority areas.
Syrian state media said Monday that pro-regime forces were preparing to enter the area to "join the resistance against the Turkish aggression".
"If the regime is entering (Afrin) to oust the PKK, YPG, there is no problem. But if they are entering to protect the YPG, then no one can stop us and Turkish soldiers," Cavusoglu said.