DAMASCUS — The death toll in the world’s most brutal conflicts climbed by more than 28 percent last year from 2013 with bloodshed in Syria worse than all others for the second year running, according to a study released on Wednesday.

The Project for the Study of the 21st Century think tank analyzed data from sources including the United States military, the United Nations, the Syria Observatory for Human Rights and Iraqi Body Count which showed more than 76,000 people were killed in Syria last year, up from 73,447 in 2013.

Many of the most violent wars involved radical Islamist groups.

Around 21,000 lives were lost in Iraq as the government fought with “Islamic State”, followed by Afghanistan with 14,638 and Nigeria with 11,529, according to the analysis which the think tank said could easily underestimate reality.

“Assessing casualty figures in conflict is notoriously difficult and many of the figures we are looking at here are probably underestimates,” said PS21 Executive Director Peter Apps.

“The important thing, however, is that when you compare like with like data for 2014 and 2013, you get a very significant increase.”

Ukraine’s separatist conflict in the east of the country propelled it onto eighth on the list, having been largely conflict free in 2013.