At least 92 civilians have been killed in Syria as violence returned to the restive country, the United Nations has confirmed.
According to activists, the town of Houla in Homs Province suffered shelling on Friday, leading to the deaths of men, women and children in what is the worst bloodshed since the start of the U.N peace plan.
It has also been reported that civilians were fired upon by forces loyal to the country's president, Bashar Al-Assad, during protests in Damascus and Aleppo.
Videos have appeared on YouTube purporting to show the aftermath of the artillery barrage in Houla, with the blood-soaked bodies of children being placed in makeshift mortuaries.
According to the head of U.N. team monitoring the supposed ceasefire, "Military and civilian observers went to Houla and counted more than 32 children under the age of 10 and over 60 adults killed."
Major General Robert Mood said: "The observers confirmed from examination of ordinances the use of artillery tank shells."
The Norwegian added: "Whoever started, whoever responded and whoever carried out this deplorable act of violence should be held responsible."
The exact number of people killed over recent days isn't clear due to restrictions on reporting in Syria.
Syrian opposition put the total at more than 100, while the Syrian government news agency reported that 13 had instead been killed by anti-government insurgents,
"More than 110 people were killed (half of whom are children) by the Syrian regime's forces", the Syrian National Council said in a statement.
The violence was sparked by anti-government forces retaliating to shelling by Assad's forces, according to The Guardian.
Local activist Abu Yazan told the paper that the shelling killed 12 people, with 106 killed by pro-regime thugs called "shabiha".
He said: "They killed entire families, from parents on down to children, but they focused on the children."
The attacks come as the former UN Secretary General Kofi Annan, who arbitrated a ceasefire between government forces and the rebel Free Syrian Army (FSA), prepares to return to the country.
The ceasefire deal has been repeatedly violated, and Annan is returning to the country to attempt to renegotiate a pact.
UN Secretary General Ban Ki-Moon recently blamed President Al-Assad for reneging on a peace deal in recent months.
Ban condemned the "unacceptable levels of violence and abuses" that have been happening daily in the Middle Eastern country.
The Syrian Observatory for Human Rights, meanwhile, issued a strongly worded statement claiming that the UN has blood on its hands.
It said: "We have reported the siege of the city and the death of a civilian this afternoon, yet no monitors moved into the area.
"We therefore inform the UN monitors that if their mission is merely to report breaches to the ceasefire and document the number of those killed in Syria, then the ink they are using is the blood of the Syrian people, we hope their consciences awake soon."
The UN is moving monitors into Houla on Saturday, according to The Associated Press.