The US Senate on Tuesday approved President Donald Trump's $500m sale of Joint Direct Attack Munitions (JDAMs) for use in Yemen by Saudi Arabian Air Force (SAAF).
The Senate voted 53-47 to defeat a resolution of disapproval that had been offered by a group of bi-partisan senators against the precision-bombs sale.
The JDAMs are meant to destroy concrete bunkers and similar heavily fortified defenses. But human rights groups have accused the SAAF of dropping these highly destructive bombs in heavily populated civilian areas.
One in three Saudi airstrikes were hitting crucial civilian and economic infrastructure such as schools and markets, the Guardian had reported in 2016.
"What is happening today in Yemen is a humanitarian crisis," one the senators who moved the motion, Senator Murphy said. "The United States supports the Saudi-led bombing campaign that has had the effect of causing a humanitarian nightmare to play out in that country."
President Barack Obama withheld sale of the guidance systems in 2016 out of concern the Saudis were deliberately attacking civilians and critical infrastructure in Yemen, already one of the world's poorest nations before the war.
More than 4,125 civilians have been killed and more than 7,200 civilians have been wounded in Yemen since the Saudi-led air campaign started in March 2015, according to a recent report by Human Rights Watch. Most of those casualties resulted from Saudi coalition air strikes.