Human Rights Watch voiced concern on Thursday that an airstrike by the Saudi-led coalition on a warehouse of the aid group Oxfam appears to have violated the laws of war.

Human Rights Watch voiced concern on Thursday that an airstrike by the Saudi-led coalition on a warehouse of the aid group Oxfam appears to have violated the laws of war.

The strike occurred on April 18 at Oxfam's facility in the northern city of Sadaa, killing and injuring dozens of civilians.

Under the laws of war "civilians and civilian objects may never be deliberate targets of attack," the New York-based watchdog said in a statement.

"The fact that the Oxfam warehouse should have been known to the coalition forces raises concerns that the attack was deliberate."

Oxfam's Yemen country director, Grace Ommer, called the warehouse attack "an absolute outrage."

She said the British-based charity told the coalition where its offices and storage facilities were located.

"The contents of the warehouse had no military value," but contained material related to the group's provision of clean water to thousands of households in Sadaa, Ommer said in a statement.

According to the United Nations, millions of people have been affected by conflict in Yemen, where they are struggling to access healthcare, water, food and fuel.

"The dire humanitarian situation in Yemen is made worse by attacks on relief supplies," Human Rights Watch said.

The Saudi-led coalition declared an end Tuesday to its aggression on Yemen, nearly a month after launching air strikes against the civilians in the impoverished Arab country on March 26.

According to reports, about 2,800 people have been killed during the aggression, and thousands others were injured.