UNITED NATIONS, Aug. 17 (Xinhua) -- The top UN official for humanitarian affairs on Friday called for the protection of aid workers and civilians in armed conflict.

Mark Lowcock, UN undersecretary-general for humanitarian affairs and emergency relief coordinator, made the appeal on the occasion of the World Humanitarian Day, which falls on Aug. 19.

Last year, 139 aid workers were killed, 102 were wounded and 72 were kidnapped in the line of duty. This marks the fifth consecutive year in which more than 100 humanitarians lost their lives on the job, and it is the highest recorded annual death toll since 2013, when 156 humanitarians were killed, said Lowcock in a press release.

"It is unconscionable that civilians and the aid workers who are trying to help them are killed and maimed in conflict zones with utter impunity. We need this to end."

In 2017, three out of four of the 43,000 people reportedly killed or injured by explosive weapons were civilians, a 38-percent increase from 2016, said Lowcock.

Governments and non-state armed groups have clear legal obligations to protect civilians and civilian infrastructure, protect aid workers and ensure the safe and unimpeded passage of supplies in armed conflict, he said. "It is imperative that we hold men with guns and power accountable when civilians and aid workers are illegally targeted."

Aug. 19 was designated as World Humanitarian Day by the UN General Assembly in 2008 to mark the bombing that targeted the UN Assistance Mission in Iraq on Aug. 19, 2003. The blast at the Canal Hotel in Baghdad killed 22 people, including the world body's top envoy in Iraq, Sergio Vieira de Mello.