The devastating civil war in Syria has claimed the lives of more than 19,000 children since the conflict began in 2011, according to new estimates tabulated by the Syrian Human Rights Network. The report found that 18,858 Syrian children were killed by government forces, mostly through missile shelling and the use of barrel bombs in active conflict zones, from March 2011 through October 2015. 582 children were shot by snipers and 159 were tortured to death in government prisons, the group wrote. Rebel forces killed an additional 603 children in that time frame, and another 229 died at the hands of the Islamic State militant group. Since September, Russian airstrikes have resulted in the deaths of at least 86 children, while airstrikes by U.S.-backed coalition forces have killed 75, the report said. The influx of Syrian refugees into Europe has stoked a continent-wide crisis in recent years. But a newer debate around how many refugees to accept, and how to screen them, has cropped up in Europe and the United States in recent days amid fears that terrorists could try to infiltrate refugee groups. Various human rights groups put the total civilian death toll from the Syrian conflict at around 200,000, making child deaths around 10 percent of the carnage. But death counts have been overwhelmingly difficult to calculate; the United Nations announced last year it would stop updating its estimates.