More aid workers have been killed this year than in any year since tallies began, the U.N. humanitarian office said on Friday, with most of them killed in the Gaza conflict.

So far this year there have been 281 aid worker victims, according to the Aid Worker Security database which has recorded incidents dating back to 1997, versus 280 in 2023 which held the previous record.

It showed 178 had been killed in the occupied Palestinian territories including Gaza this year which has been the deadliest conflict for the United Nations. Twenty-five were killed in Sudan, it showed.

"These people are doing God's work, and they're being killed in response. What the hell?" said Jens Laerke, spokesperson for the U.N. Humanitarian Office (OCHA), at a Geneva press briefing.

Most of the victims were local staff, while 13 of them were international aid workers, he added.

Aid workers enjoy protection under international humanitarian law but experts cite few precedents for such cases going to trial, with concerns about ensuring future access for aid groups and difficulty proving intent cited as impediments.

"This violence is unconscionable and devastating to aid operations," said U.N. aid chief Tom Fletcher in a statement.

"States and parties to conflict must protect humanitarians, uphold international law, prosecute those responsible, and call time on this era of impunity," he said.