CNN reported on Monday that Saudi Arabia and the United Arab Emirates, its main partner in the coalition, have transferred USA -made weapons to al Qaeda-linked fighters and other groups and that some of the weapons also made their way into the hands of Iranian-backed rebels, exposing sensitive technology to Iran.
An investigation, carried out by CNN, has found that Saudi Arabia and the United Arab Emirates had allegedly used weapons provided to them by the United States as currency to buy off militias and factions in the Yemeni conflict.
"These reports are very troubling and the Trump administration must investigate further and work to prevent this from happening again", Engel, a Democratic Representative, said at Wednesday's hearing.
Investigations by the Amman-based Arab Reporters for Investigative Journalism and CNN showed that the arms had fallen into the hands of extremist groups like al-Qaida.
The investigation also found that U.S. weapons also made their way into the hands of Iranian-backed rebels who are battling the Gulf coalition for control of the country, exposing some of America's sensitive military technology to Tehran.
"Neither the threats facing the Saudis nor America's partnership with the kingdom mean that the Saudis should have a blank check", said new committee Chairman Eliot Engel, New York Democrat.
According to publicly available data, since the outbreak of the Yemeni conflict in March 2015, Western states have supplied the UAE with at least $3.5 billion worth of arms.
The State Department said it was investigating the allegations.
"We are aware of these reports and seeking additional information", a department official said, adding that all such reports are taken seriously, Reuters reported. Other weapons used by UAE-allied militias in Hodeidah include Serbian-made Zastava MO2 Coyote machine guns and the Agrab armored-truck-mounted Singaporean 120mm mortar system - the UAE is the only country known to purchase this combined weapon system.
The U.S. has helped fuel the disaster with weapons, logistical assistance, and refueling of aircraft so the Saudi-led coalition can wage its bombing campaign.
Committee's top Republican Michael McCaul called Khashoggi's murder a "major setback" in the Saudi-US ties and deplored casualties in Yemen. He said, "It can no longer be business as usual".
So why don't we hold Saudi Arabia to the same human rights standards as other countries?
The Senate approved the measure in November over the Trump administration's objections.
In December, a similar bill cleared the Senate in a 56-41 vote but was blocked by the House, which was then under the control of Republicans.