Human Rights Watch said Thursday that an airstrike by the Saudi-led coalition in Yemen that killed at least 29 people earlier this week "raised grave concerns about violations of the laws of war."
The group called on the forces involved in the attack to conduct an investigation, and for the United States, which is giving logistical and intelligence support, to make sure precautions are being taken to protect Yemeni civilians.
"The deaths of so many civilians in a camp with no apparent military target heightens concerns about laws-of-war violations," said Joe Stork, HRW's Middle East and North Africa director.
United Nations Secretary-General Ban Ki-moon said he was "deeply concerned" about the attack Monday on the Al-Mazrad camp in northern Yemen as well as other civilian casualties in Yemen.
On Wednesday, at least 35 people died in an explosion at a dairy in western Yemen. The cause of that blast has not been determined with conflicting reports about whether another airstrike or anti-government fighters were responsible.