Morale is running low among fighters in northern province as regime forces gain ground.
Almost 93,000 people were killed in Syria’s conflict by the end of April this year, but the true number could be “potentially much higher”, the UN has said.
The exact figure released on Thursday – 92,901 people – is much higher than the UN’s last death toll back in January of 59,000 people.
“The constant flow of killings continues at shockingly high levels,” said Navi Pillay, the UN high commissioner for human rights. “This is most likely a minimum casualty figure. The true number of those killed is potentially much higher.”
An average of more than 5,000 people have been killed every month since last July, while rural Damascus and Aleppo have recorded the highest tolls since November, the report said in its latest study compiling documented deaths.
Among the victims were at least 6,561 children, including 1,729 children younger than 10.
Rupert Colville spokesman for Pillay, told Al Jazeera that it had under-reported the number of deaths because of constraints on estimations owing to the conflict.
“We’re reliant, really, on some very brave activists who since the beginning of this conflict have done their best to keep track of how many people have been killed,” Colville said.
The report said UN teams on the ground and activists had found evidence of children being tortured during the conflict.
“We’ve all seen videos and photos of children who have been tortured to death, children who have been summarily executed,” Colville said.
“We’ve seen entire families that have been slaughtered, including babies even, and then you’ve got children who have been killed by indiscriminate shellfire, missiles, aerial bombardment and a general, no-holds-barred conflict.”
Fighting continued across Syria on Thursday. A mortar round struck an area near the runway at Damascus International Airport, briefly disrupting flights, officials said.
It was the first known attack to hit inside the airport, south of the capital, and came weeks after the government announced it had secured the airport road that had been targeted by rebels.
Mahmoud Ibrahim Said, Syria’s Transport Minister, told state television the attack delayed the landing of two incoming flights, from Latakia and Kuwait, and the take-off of a Syrian flight to Baghdad. No passengers were harmed and no planes were damaged, he said.
The Britain-based Syrian Observatory for Human Rights said rebel fighters had targeted the airport with homemade rockets.
Rebels also battled regime forces for control of a key military base in the central Hama province after chasing soldiers out and setting fire to installations there, activists said.
Following dawn battles, rebels took control of the base on the northern edge of the town of Morek, which straddles the country’s strategic north-south highway leading to Aleppo.
By midday, regime forces shelled the base and sent reinforcements in an apparent attempt to regain control of the area, said the Observatory said.
The Observatory, which has a vast network of Syrian activists on the ground, said the rebels killed six government fighters and seized ammunition and weapons. Two rebel fighters were killed.
State-run TV reported on Thursday that troops had secured four towns in the central province of Hama after killing 60 members of Jabhat al-Nusra. It said the towns included Masaadah, Abu Hanaya and Abu Jbeilat.
On the international front, the UN is in exploratory talks with Sweden about its participation in a beefed-up peacekeeping force between Syria and the Israeli-occupied Golan Heights, officials from the two countries said.
The UN has asked Swedish Foreign Minister Carl Bildt whether Stockholm would consider sending troops to the UN Disengagement Observer Force after Austrian troops have begun withdrawing as a result of attacks and abductions of
The Obama administration is meeting this week on whether to arm the Syrian rebels, a topic that US Secretary of State John Kerry has discussed with his British counterpart William Hague in Washington.
The meetings come ahead of a G8 summit in Northern Ireland next week.
G8 leaders are expected to discuss a co-ordinated response to the Syrian conflict, and how to bring the rival sides together at a peace conference.