Violence against aid workers hit a record high last year, according to research released Tuesday.
London-based consultancy group Humanitarian Outcomes says worldwide 155 aid workers were killed, 171 seriously wounded and 134 were kidnapped in 2013.
The group's Aid Worker Security Report says the numbers represent a 66 percent increase in victims from 2012.
Three-quarters of the attacks took place in just five countries - Afghanistan, Pakistan, South Sudan, Sudan and Syria. Afghanistan had the highest number of attacks on aid workers.
And 2014 is proving to be another bad year for humanitarian aid operations, with the report showing 79 workers killed up so far this year - already topping the 2012 death toll of 70.
Tuesday's release of the findings coincides with the United Nations-designated World Humanitarian Day.
At a special U.N. Security Council session Tuesday, Masood Karokhail of Afghan NGO The Liaison Office said native Afghans are bearing the brunt of the violence against aid workers in his country. He said international organizations are using local staff to reduce their own security risk.
In a statement marking World Humanitarian Day, U.S. Secretary of State John Kerry said that "as the world's largest donor of humanitarian assistance," the United States remains "steadfast" in its commitment to doing everything it can to provide for humanitarians' safety and security.
World Humanitarian Day falls on the anniversary of the 2003 attack on the U.N. headquarters in Baghdad, which killed 22 aid workers.