The death toll in Syria's civil war has risen to at least 125,835, more than a third of them civilians, but the real figure is probably much higher, the Syrian Observatory for Human Rights said on Monday.
The pro-opposition monitoring group also appealed to UN Secretary General Ban Ki-moon and "all people in the international community who have a conscience" to increase their efforts to end the 2-1/2 year war.
The conflict began as peaceful protests against four decades of rule by President Bashar Assad's family, but under a fierce security force crackdown, turned into an armed insurgency whose sectarian dimensions have echoed across the Middle East.
The Observatory, based in Britain but with a network of activists across Syria, put the number of children killed in the conflict so far at 6,627.
It put the death toll among rebels fighting the Assad government at at least 27,746 rebels, including more than 6,000 categorized as foreign fighters or unknown combatants.
"The number is likely much higher but in many battles, the number of rebels killed is hidden, especially by the (al Qaeda-linked) Nusra Front and Islamic State of Iraq and the Levant," Rami Abdelrahman, head of the Observatory, told Reuters.
He said the observatory had documented 50,430 deaths among the Syrian armed forces and local militias supporting Assad, but said that number too was probably higher.