An activist-run Syrian war monitor estimates that around 560,000 people, including fighters and civilians, have died since the start of the Syrian conflict in 2011.
The UK-based Syrian Observatory for Human Rights said on Monday that it had identified more than 367,000 of those killed by name.
The updated death toll, released on the occasion of the 70th anniversary of the Universal Declaration of Human Rights, said around 111,330 civilians were among those killed.
The toll, however, does not include around 88000 people allegedly killed in government-run prisons, the SOHR says.
Realities on the ground make it increasingly hard to pinpoint precise numbers and international organisations have stopped monitoring the death toll in Syria because they say they are unable to verify source material on deaths.
The UN, which released regular reports on the death toll during the first years of the war, has stopped documentation efforts because it doesn't have full access to the country. Its last estimate in 2016 put the number of those killed at 400,000.
Activist-run monitors, including the SOHR, are still compiling casualty estimates by working with contacts on the ground and collecting open source reports from the news and social media networks.
However, their numbers have not been verified by international groups and vary widely between one organisation and the other.
The Syrian Network for Human Rights, which uses tactics similar to those of the SOHR to track deaths, has put the death toll at 222,114 since the start of the war. However, the group only counts civilian deaths, while the SOHR also tracks the death of fighters, insurgents and Syrian troops.
The Violations Documentation Center (VDC), another activist-run monitor, says that a total of 190,891 people have been killed between March 2011 and October 2018.
Fighting has dialled-down in Syria in recent months after Syrian government forces and their allies regained control of several strategic opposition-held areas, including the Eastern Ghouta suburbs of Damascus.
Syria’s government held just 20 per cent of the country at the beginning of 2017, but it now controls more than 60 per cent of Syrian territory.
The government has also routed ISIS from some of its main strongholds in Syria, including holdouts in southern Syria and the eastern province of Deir Ezzor in recent months.
Militants continue to command a pocket near the Iraqi border, but they are coming under constant attack by a US-backed coalition of Kurdish and Arab fighters.
Although fighting has winded-down, a highly-anticipated battle looms over Idlib province, the last major rebel stronghold in the country.
Russia and Turkey brokered a deal in September to create a demilitarized zone in the province, in an attempt to prevent a military offensive on the area.
However, the deal has been undermined by routine violations committed by both rebels and the Syrian government, leading to concerns that the agreement may collapse.
The UN and international aid organizations have warned that an offensive on Idlib would mark the worst humanitarian catastrophe in Syria since the start of the war.
Idlib is home to more than 2.5 million people, nearly half of whom have been displaced from other parts of the country.