The U.N. Staff Union says at least 71 U.N. staff and associated personnel were killed in "malicious acts" in 2017, the highest number ever recorded by its committee on security.

It said 53 peacekeepers and 18 civilians, including two police personnel and 15 contractors, lost their lives last year, bringing the five-year total of U.N. personnel killed in deliberate attacks to at least 310.

The Staff Union said Wednesday that the U.N. peacekeeping mission in Mali suffered the greatest loss of life for the fourth year, with 21 peacekeepers and seven civilians killed in 2017.

It also said Congo was the second deadliest U.N. mission, with 15 Tanzanian peacekeepers killed on Dec. 7 in the worst attack on U.N. peacekeepers since 1993, along with six civilians killed in 2017.