The London-based Syrian Observatory for Human Rights claims it has about 200 contacts in Syria monitoring the conflict, now in its third year. The organization said the mortality figures, for all sides, stood at 150,000 at the start of April, but that number has since risen to about 162,000.
The United Nations stopped offering estimates earlier this year, noting problems with verification. Combatants typically suppress information, journalists seeking accurate counts face the normal obstacles of war, and social media often mix propaganda with fact.
Syrian Observatory's reports have been criticized by both pro-government and rebel forces in Syria, an indication, director Rami Abdul Rahman said, that his organization is on the right track. He noted, though, that no one can know "the entire reality" of the war, which has displaced half of Syria's population.
The current totals from the Syrian Observatory, on the pro-government side, include 37,685 deaths in the Syrian army, 23,485 in pro-government militias, 438 Hezbollah members, and 1,224 other non-Syrian, pro-government fighters.
It added 42,701 anti-government forces have been killed, as well as 53,978 civilians, 8,607 of whom were children.