A pregnant woman and three children were among 18 civilians killed when Syrian rebels shelled a Kurdish neighbourhood in the northern city of Aleppo, a monitor said Wednesday.
The Britain-based Syrian Observatory for Human Rights said 70 people, including 30 children, were also wounded in Tuesday's attack, adding that the shelling was a violation of a ceasefire agreement.
"A major shelling attack on Tuesday has left 18 civilians dead, including three children and two women, a pregnant one and an elderly one," according to the Observatory.
The attack targeted the majority-Kurdish neighbourhood of Sheikh Maqsud, where some 50,000 residents are caught in the crossfire of regime-held districts and those controlled by rebels.
"This is a very clear violation of the ceasefire" in place in Syria since February 27, said Observatory head Rami Abdel Rahman said.
Rebels including Ahrar al-Sham, which is allied to Al-Qaeda in Syria, kept up Wednesday their shelling of Sheikh Maqsud which overlooks regime-held areas, said the Observatory.
Abdel Rahman said the rebels want to take the neighbourhood because it would allow them to have "a launching pad for attacks" on government forces.
Aleppo became a divided city in 2012 after a rebel onslaught was met with resistance by the army.
Kurds represent about 15 percent of Syria's population and have tried to avoid confrontation with the regime or non-jihadist rebels since war broke out in 2011.
But the rise of the Islamic State group (IS), which has seized large swaths of the war-torn country, has seen the Kurds lead the fight against the militants in parts of Syria.
On March 17, Kurdish parties, including the powerful Democratic Union Party (PYD) and their allies, announced the creation of a "federal system" in northern Syria.
The announcement was heavily criticised by Syria's opposition, who have vowed to use "all the political and military force" at their disposal to fight it.
Syria's conflict erupted in March 2011 with anti-government protests but has since morphed into a multi-front war drawing in regional powers.