US unsuccessfully targeted 

The US has long accused Iran of supplying the Houthis with missiles and other sophisticated weapons that they have used in those attacks.

The conflict in Yemen began in early 2015 when Houthi rebels -- a minority Shia group from the north of the country -- drove out the US-backed government and took over the capital, Sanaa.

The crisis quickly escalated into a multi-sided war, with neighboring Saudi Arabia leading a coalition of Gulf states against the Houthi rebels.

A report from the Armed Conflict Location & Event Data Project last June found that more than 91,000 people have been killed in the conflict since 2015. It also found that the Saudi-led coalition and its allies had been responsible for more than 8,000 of the approximately 11,700 deaths connected to the direct targeting of civilians in the conflict.

Last year, in a rare moment of bipartisanship, both the House and Senate passed a resolution (SR7) that called on the Trump administration to end all hostilities in Yemen that weren't expressly authorized by the Congress. President Donald Trump vetoed the resolution in April and the support of the Saudi-led effort in Yemen continues.

The Trump administration has been insistent that is the President's job to enact US foreign policy and that any attempt to limit his authority is inappropriate. In his veto message in response to SR7, Trump argued that Congress was the one overstepping its bounds.

"This resolution is an unnecessary, dangerous attempt to weaken my constitutional authorities, endangering the lives of American citizens and brave service members, both today and in the future," Trump wrote.