The Hudaydah operation began while Washington’s attention was still focused on the summit meeting between President Trump and North Korea’s leader, Kim Jong-un. It was not immediately clear what role, if any, American military advisers would play in the campaign. The New York Times reported last month that United States Army commandos were helping to locate and destroy caches of ballistic missiles and launch sites that Houthi rebels were using to attack Saudi cities.
Since 2015, the United States has provided the Saudi-led air campaign in Yemen with air-to-air refueling, intelligence assessments and other military advice, but even those roles have been contentious.
The Pentagon insists that all of its military aid is noncombat assistance, like advising the Saudi Air Force on adopting bombing practices that kill fewer civilians. But at the same time, the defense contractor Raytheon is courting lawmakers and the State Department to allow it to sell 60,000 precision-guided munitions to the Saudis and Emiratis, in deals worth billions of dollars.
American advisers do not give direct or indirect approval on target selection or execution of bombings against Houthi rebels, Pentagon officials say. Rather, they give advice on targeting procedures and facilitate checks of a list of “no-strike” buildings, like mosques and marketplaces.
“It’s providing any intel, or anything we can give to show no-fire areas where there are civilians, where there’s mosques, hospitals, that sort of thing,” Mr. Mattis, the defense secretary, told reporters at the Pentagon on Monday, when asked about American support to the impending offensive.
Maj. Adrian J. Rankine-Galloway, a Pentagon spokesman, said on Wednesday that these intelligence-sharing procedures had not changed in the prelude to the offensive, and that the United States was not providing specific information on Houthi targets for Saudi Arabia or the United Arab Emirates.
An increasing number of Republican and Democratic lawmakers in Congress are criticizing even this limited role, accusing the Pentagon of being complicit in the errant bombing campaign.