A police trooper walks in a creater caused by an air strike on houses near Sanaa Airport, Yemen, on March 31, 2015.

(Beirut) – The airstrikes by the Saudi Arabia-led coalition that hit a displaced persons’ camp in northern Yemen on March 30, 2015, raised grave concerns about violations of the laws of war. The airstrikes killed at least 29 civilians and wounded 41, including 14 children and 11 women. They hit a medical facility at the camp, a local market, and a bridge, according to initial reports from the World Health Organization.

All government forces participating in the attack should impartially investigate whether there were violations of the laws of war and take appropriate action, Human Rights Watch said. The United States, by providing intelligence to the Saudi-led air campaign, shares the obligation to minimize harm to civilians and civilian property in the fighting.

“The deaths of so many civilians in a camp with no apparent military target heightens concerns about laws-of-war violations,” said Joe Stork, deputy Middle East and North Africa director at Human Rights Watch. “All sides in Yemen’s conflict need to do what they can to avoid harming civilians.”

Sometime before 11 a.m. on March 30, one or more warplanes of unidentified nationality struck multiple sites at one of the three camps for internally displaced persons (IDPs) in Mazraq, in Hajja governorate of northern Yemen, about six kilometers from the border with Saudi Arabia.

Khaled Mareh, one of the camp managers, told Human Rights Watch that at 10:50 a.m., as he was standing at the camp gate, an explosion knocked him back: “I first heard the sound of a distant plane, then the deafening explosion. I saw body parts scattered in front of me, charred bodies, torn tents, and a large amount of shrapnel that hit the gate and charred the cars.” He said he saw a second explosion hit a section of the camp about 500 meters away, which he later learned killed several children from the camp who were walking to school. From a distance, he saw a third explosion at the western gate of the camp, and a fourth that hit the market.

A local aid worker present at the time said that he saw one aircraft carry out a strike at the camp: “I saw the plane strike 500 meters from the International Organization for Migration office. It shook the building and rattled the windows.” The United Nations Humanitarian Coordinator to Yemen, Johannes Van Der Klaauw, stated on March 31 that all the structures hit constituted civilian infrastructure.

Reuters reported that an aid worker said that a warplane had struck a truck at the gate to one of the camps carrying fighters from Ansar Allah, the Houthi armed wing. The Guardian reported  that some aid workers believed the attack was targeting a nearby base for Houthi fighters, a claim that Human Rights Watch could not confirm. Even if several Houthi fighters or a military truck were present at the camp, the attack was still probably unlawfully indiscriminate or disproportionate, Human Rights Watch said.

Mareh, the camp manager, said that Ansar Allah has a security office at the camp, near the market, but that it had been empty for three days, since the guards left to join military operations at the border. He said he did not hear any artillery or other fire in the area before the strikes, and that the camp authorities never allow armed people to enter the camp, including that morning. Another witness told Human Rights Watch that he did not see any armed men at the camp prior to the strikes, nor did he hear any fire.

None of the countries participating in the coalition have provided information that the camps are a legitimate military target. When asked about the strikes, a Saudi military official, Brig. Gen. Ahmad al-Assiri, said, “It could have been that the fighter jets replied to fire, and we cannot confirm that it was a refugee camp.”

Medecins Sans Frontieres, which supports a hospital in the vicinity, confirmed that its staff treated dozens of people wounded by the airstrikes that day, and received the remains of some people who had been killed. An aid worker at the hospital told Human Rights Watch, “We received a number of charred bodies, truncated limbs and others with very severe wounds.”

A full investigation is needed to determine whether the airstrikes on the camp violated the requirement under the laws of war for attacks to be directed at a legitimate military target, Human Rights Watch said. The laws of war, which apply to the armed conflict in Yemen, prohibit attacks that target civilians or civilian property, that do not or cannot discriminate between civilians and combatants, or that cause harm to civilians or civilian property that is disproportionate to any anticipated military advantage. All parties to the conflict have an obligation to take all feasible precautions to spare civilians from harm, and not to deploy forces in densely populated areas.

Following the attack, over 400 residents fled the camp and are seeking refuge elsewhere, Mareh said.

The three camps, two of which are still operating, have been housing about 12,500 people, according to the Office of United Nations High Commissioner for Refugees (UNHCR), which established them in 2001. Most of those living there had been displaced by fighting in Saada governorate between Houthi and Yemeni government forces between 2004 and 2010.

In January 2015, the Houthis effectively ousted the government of President Abdu Rabu Mansour Hadi. The Saudi-led airstrikes, which started on March 26, killed at least 11 civilians and possibly as many as 34 in Sanaa on the first day. Saudi and other aircraft also struck targets in other cities, including Saada, Hodaida, Taiz, Lahj, al-Dale`a, and Aden. On March 29, officials of the Ansar Allah-controlled Health Ministry said that the civilian death toll the previous night was 35. According to the United Nations Office of the High Commissioner for Human Rights, since March 27, the fighting in Yemen has killed at least 93 civilians and wounded 364.

In addition to Saudi Arabia, the United Arab Emirates, Kuwait, Bahrain, Qatar, Jordan, Morocco, and Sudan said that their aircraft are participating in the airstrikes. Pakistan and Egypt said they are providing naval support. The United States has confirmed it is sharing intelligence and providing targeting assistance as well as logistical support, including air refueling of warplanes.

Human Rights Watch earlier raised concerns about Saudi Arabia’s possible use of cluster bombs in the operation, given credible evidence of past use of cluster bombs by Saudi Arabia in Yemen in 2009. At a news conference in Riyadh on March 29, Brig. Gen. al-Assiri responded to a media question about the issue, saying, “We are not using cluster bombs at all.” Saudi Arabia should make clear that it will not use cluster munitions under any circumstances, Human Rights Watch said.

“All countries participating in the camp attack, and that could include the US, have an obligation to investigate possible laws-of-war violations,” Stork said. “The US needs to make sure that the coalition it is supporting is taking the necessary precautions to avoid civilian loss of life and property.”