The bomb in the deadly Yemen school bus attack that killed 51 people was manufactured by a U.S. firm, according to a CNN investigation with local Yemeni journalists and munitions experts.
The laser-guided MK 82 bomb was made by defense giant Lockheed Martin, CNN reported.
The report reawakens long-standing questions over the degree of the United States's complicity in the ongoing war in Yemen. The U.S. supplies arms and intelligence to Saudi Arabia.
Forty of those killed in last week's bus bombing were children, as were 56 of the 79 who were wounded, Houthi Health Minister Taha al-Mutawakil said last week.
Saudi Arabia defended the incident as a "legitimate military operation," CNN reported.
The U.S. backs the Saudi-led coalition responsible for the bombing. The coalition is fighting a Houthi rebel insurgency in Yemen, and has attracted international condemnation for its targeting of civilians.
The Yemen Data Project has collected evidence that the Saudi-led coalition has launched 55 airstrikes against civilian vehicles and buses since the beginning of 2018, the Guardian reported.
U.S. weapons have been the source of mass civilian casualties in Yemen before. In 2016, a similar bomb killed 155 people in a funeral hall attack, CNN reported. A US-supplied MK 84 bomb reportedly killed 97 people in March 2016, a few months before that.
The final version of this year's defense policy bill would put conditions on the U.S. refueling of Saudi and Emirati planes bombing Yemen.
President TrumpDonald TrumpClyburn says he's worried about losing House, 'losing this democracy' Sinema reignites 2024 primary chatter amid filibuster fight Why not a Manchin-DeSantis ticket for 2024? MORE on Monday signed a defense spending bill that requires the Pentagon and State Department to certify that Saudi Arabia is working to reduce civilian casualties.
Hundreds of people gathered on Aug. 14 to mourn the children killed the airstrike, CNN reported.
“We never expected this to happen,” Abdel-Ilah Mohammad, the father of a young boy killed in the attack, told CNN. “He walked out of the door with white clothes. He put on perfume and combed his hair before he left; he didn’t need to — he was a handsome boy. He did not know what was coming for him.”