LONDON: The death toll in the world's most brutal conflicts climbed by more than 28 per cent 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 analysed 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 on 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.

At least 14 separate wars killed more than 1,000 people in 2014, up from 10 in 2013.

The research points to a developing trend.

Last year the Australia and US-based Institute for Economics and Peace reported a rise in conflict-related violence every year since 2007.