Iran has formally complained to the United Nations, saying the US has committed a “war crime” by deliberately targeting two Iranian maritime search-and-rescue vessels, saying the ships were engaged solely in humanitarian operations, IRNA reports.

In a letter addressed to UN Secretary-General António Guterres and the president of the UN Security Council, Iran’s Ambassador to the UN Gholamhossein Darzi recalled that the US attacked the Iranian rescue vessels Naji-15 and Naji-16 during the early hours of July 23 while they were operating in Iran’s territorial waters off Hormozgan Province.

Darzi said the two vessels were dedicated exclusively to maritime search-and-rescue missions and were protected under international humanitarian law and the law of the sea.

“By deliberately targeting humanitarian search and rescue assets, the United States has not only endangered the lives of rescue personnel, but has also placed at risk all mariners in distress, regardless of their nationality,” the letter read.