Washington, August 20 (RHC)-- Munitions experts have confirmed that a bomb used by Saudi Arabia in last week's attack on a school bus in Yemen that killed dozens of children had been supplied by the United States .

The experts told CNN that the bomb was a 227-kilogram laser-guided Mark 82 bomb.  They also noted that the numbers on the weapon identified major U.S.  military contractor Lockheed Martin as its maker. 

The Saudi air raid on Sa'ada hit a school bus on August 9th as it drove through a market in the town of Dhahyan, sparking outrage from international human rights groups and UN officials.  The attack killed a total of 51 people, among them 40 children, and left 79 others wounded. 

Last week, a local journalist said recovered bomb fragments showed that it was likely manufactured in the U.S. 

Riyadh initially described the Sa'ada strike as a "legitimate military action," but later launched an investigation into the incident amid mounting criticism of its bloody war on Yemen. 

Asked about CNN's report, Saudi coalition spokesman Colonel Turki al-Maliki said that it would not "be appropriate to comment further while the investigation is underway."  

The report also said that the bomb used in the Sa'ada airstrike was very similar to the one that hit a funeral hall in the Yemeni capital, Sana'a, in October 2016, killing 155 people and injuring 525 others.