Human Rights Watch, which chairs the Cluster Munition Coalition U.S., has reported credible evidence that airstrikes by Saudi Arabia in Yemen have used cluster munitions supplied by the United States. None of the members of the Saudi Arabia-led coalition are part of the 2008 Convention on Cluster Munitions, which prohibits use of the weapons, including the CBU-105 used in airstrikes against Houthi forces in northern Saada governorate. Yemen and the US are also not part of the ban treaty. 

There is no information on possible casualties from the attacks. The evidence provided by Human Rights Watch includes photographs, video, and witness testimony:

• A video uploaded to YouTube on April 17 shows numerous munitions with distinctive, white parachutes descending from the sky and zooms out to show a mid-air detonation and several black smoke clouds from other detonations. Using satellite imagery analysis and video forensics, Human Rights Watch has produced a graphic showing the location as al-Shaaf in Saqeen in the western part of Saada governorate. It established that weapons appeared to land on a cultivated plateau within 600 meters of several dozen buildings in four to six village clusters. 
• An activist based in the Yemeni capital, Sanaa, provided Human Rights Watch with photographs he received from a resident of Saada governorate, who said he took them on April 17 at the site of an airstrike in the al-Amar area of al-Safraa, 30 kilometers south of the city of Saada. One photograph shows an empty BLU-108 delivery canister, while the other shows a BLU-108 canister with four submunitions still attached to it, both remnants from CBU-105 Sensor Fuzed Weapons. The location of the remnants in the photographs is 36 kilometers from where the video was filmed, indicating the possibility of multiple attacks. 
• Other evidence includes accounts from two local residents of al-Safraa who told Human Rights Watch that they witnessed airstrikes in the area on April 27 involving the use of bombs with parachutes, but Human Rights Watch has been unable to determine if the weapons were CBU-105 cluster munitions or another type. 

A Human Rights Watch graphic produced from a video uploaded to YouTube on April 17, 2015 shows munitions with distinctive white parachutes descending in Al-Shaaf, in Saqueen in the western part of Saada governorate, indicating the use of CBU-105 cluster munitions. © 2015 Human Rights Watch by Human Rights Watch

Manufactured by Textron Systems Corporation, in recent years the U.S. has exported the CBU-105 Sensor Fuzed Weapons to Saudi Arabia and the United Arab Emirates (UAE) as well as India, South Korea, and other countries. In August 2013, the US Department of Defense concluded a contract for the manufacture of 1,300 CBU-105 for Saudi Arabia by Textron. The contract stipulated that delivery of the weapons should be completed by December 2015, but it is not known if the deliveries have been made. Additionally, the UAE received an unknown number of CBU-105 from Textron in 2010, fulfilling a contract announced in 2007. 

According to a Textron data sheet, the CBU-105 disperses 10 BLU-108 canisters that each subsequently release four submunitions that sense, classify, and engage a target such as an armored vehicle, and are equipped with self-destruct and self-deactivation features. The submunitions of the Sensor Fuzed Weapon explode above the ground and project an explosively formed jet of metal and fragmentation downward.

While the CBU-105 is banned under the Convention on Cluster Munitions, its export is permitted under existing U.S. export restrictions on cluster munitions while U.S. use is permitted under existing the June 2008 memorandum issued by then-Secretary of Defense Robert Gates.

Under the Gates policy, the U.S. may only export or use cluster munitions that “after arming do not result in more than 1 percent unexploded ordnance across the range of intended operational environments,” and the receiving country must agree that cluster munitions “will only be used against clearly defined military targets and will not be used where civilians are known to be present or in areas normally inhabited by civilians.”

According to guidance issued by the US Defense Security Cooperation Agency in May 2011, “the only cluster munition with a compliant submunition [compliant with the reliability standard established by the Gates policy] is the CBU-97B/CBU-105 Sensor Fuzed Weapon.”

Human Rights Watch has called on all parties to the conflict not to use cluster munitions in the Yemen fighting.  Soon after the airstrikes began, Saudi Arabia denied using cluster munitions in Yemen. At a news conference in Riyadh on March 29, Brig. Gen. al-Assiri told the media, “We are not using cluster bombs at all.” 

Previously, U.S. cluster munitions were used in Yemen in 2009 by Saudi Arabia in Saada governorate in November and by the US in southern Abyan governorate on December 17.

In a March 30 letter, the Cluster Munition Coalition U.S. urged President Barack Obama to initiate a review of the 2008 Gates policy on cluster munitions, including the exception allowing for cluster munitions resulting in less than 1 percent unexploded ordnance rate.

Coalition chair Human Rights Watch has described the provision as “a handy loophole to send cluster munitions to countries, which shouldn’t be using them at all.” 

UPDATE - May 4:

• In media interviews, Saudi Arabia's military spokesman Brig. Gen. Ahmed Asir admitted Saudi Arabia's use of the CBU-105 in Yemen, but said the cluster munition is being used against armored vehicles and not in the populated areas.
• In response to questions posed by a journalist, State Department acting deputy spokesperson Jeff Rathke said on May 4 that the US is looking at HRW's report and "we share the concerns regarding unintended harm to civilians caused by the use of cluster munitions." Rathke pointed to the commitment secured from Saudi Arabia as part of the transfer deal "that cluster munitions will be used only against clearly defined military targets." The reporter asked "Why is it so important to use them or to continue to sell them? Is it just a money-making thing for arms manufacturers? I mean, there are clearly a lot of problems with them.Why is it U.S. policy to sell them – to transfer them at all, given the fact that you can’t guarantee this 1 percent rate? And some might argue that even 1 percent is too much.

For more information, please see:

• Human Rights Watch press release on Saudi-led cluster munition use in Yemen
• Cluster Munition Monitor 2014 profiles on Saudi Arabia, U.S., and Yemen
• Coverage by The New York Times, Fox News, CNN, and Reuters