Ursula Mueller (R, rear), Assistant Secretary-General for Humanitarian Affairs and Deputy Emergency Relief Coordinator in the UN Office for the Coordination of Humanitarian Affairs (OCHA), briefs reporters on World Humanitarian Day, at the UN headquarters in New York, Aug. 19, 2019. The year of 2018 was the worst in five years for violence against aid workers, with at least 405 victims, Ursula Mueller said on Monday. (Xinhua/Li Muzi)

UNITED NATIONS, Aug. 19 (Xinhua) -- The year of 2018 was the worst in five years for violence against aid workers, with at least 405 victims, a UN official said Monday.

Ursula Mueller, UN assistant secretary-general for humanitarian affairs, briefed the press on the World Humanitarian Day, which is observed on Aug. 19.

The 405 victims in 35 crisis-affected countries last year also ranked the second worst on the record overall. Among them, 131 were killed, 144 wounded and 130 kidnapped.

Mueller attributed the spike of the aid worker casualties to the weakening of respect for laws of war around the world, which makes aid workers "increasingly vulnerable when they are more needed than ever before."

So far in 2019, Mueller continued, some 156 aid workers have been attacked on the job, with 57 killed, 59 wounded and 40 kidnapped.

"But even among these risks, over half a million professional humanitarian workers work every day to protect save and improve the lives of tens of millions of vulnerable people," she noted.

Aug. 19 was designated as the 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 UN staffers, including the world body's top envoy in Iraq, Sergio Vieira de Mello.

Since then, Mueller said, more than 4,500 aid workers have been killed, injured, detained, assaulted or kidnapped while carrying out their work.

Earlier Monday, the United Nations held a wreath-laying ceremony to commemorate the fallen staffers in the 2003 attack.

The ceremony took place at the Memorial Wall inside the UN General Assembly Visitors Lobby, where a flag retrieved from the bombing site is framed and hung.