U.S. Defense Secretary Jim Mattis called for a ceasefire in Yemen within 30 days, seeking to end the U.S.-backed and Saudi-led bombing campaign against Houthi rebels supported by Iran and negotiate a peace.

The coalition is seeking to reinstate the globally-recognized Yemeni government in the capital of Sanaa, currently held by the Houthis. The U.S. provides intelligence, targeting support, and training, as well as mid-air refueling for Saudi air forces. But the Trump administration’s support for Saudi Arabia and the war has drawn increasing scrutiny in recent months as the civilian death toll has mounted; in particular, an errant airstrike using a U.S.-made 500-lb. bomb that killed 40 schoolchildren this summer sparked outrage from lawmakers on Capitol Hill. The murder and dismemberment of Washington Post columnist Jamal Khashoggi in the Saudi embassy in Turkey, believed widely to be the work of Saudi Arabia, has further inflamed criticism of U.S. support for Crown Prince Mohammed bin Salman.

“The longer-term solution—and by longer-term, I mean 30 days from now—we want to see everybody around a peace table based on a ceasefire, based on a pullback from the border, and then based on the ceasing of dropping bombs that will then allow [Special Envoy Martin Griffiths] to get them together in Sweden and end this war,” Mattis said during remarks at the United States Institute of Peace, in Washington on Tuesday.

Mattis insisted that “I would separate out” the Khashoggi murder from the situation in Yemen, defending U.S. training of Saudi forces and describing them as productive efforts to help reduce civilian casualties. He also downplayed airborne refueling support, noting that the U.S. refuels “less than 20 percent” of Saudi coalition aircraft. (The news site Military.com reported in September that as of Aug. 31, Air Force tankers had carried out around 3,000 sorties providing 92.3 million pounds of fuel to coalition fighters in Yemen since the conflict began in 2015).

Defense One's full Yemen coverage can be found here.

“Our goal right now is to achieve a level of capability by those forces fighting against the Houthis that they are not killing innocent people,” Mattis said.

But a ceasefire as part of peace negotiations is “the only way we’re going to really solve this. Improved accuracy of bombs is still a war,” he said.

The top commander of U.S. troops in the region, Gen. Joseph Votel of U.S. Central Command defended U.S. support for the Saudi-led fight against the Houthis. In an exclusive interview with Defense One on Monday, Votel said he understood Congress’ criticism but argued that the U.S. was helping to improve Saudi performance. “I think it is better if we are engaged in this than if we step away from this. And, I think, my personal view is we have a better chance of trying to influence them in the conduct of this by staying engaged than we do by walking away.”

But Mattis's remarks come as the State Department has also begun to push for a November timeline for peace negotiations.

"Substantive consultations under the UN Special Envoy must commence this November in a third country to implement confidence-building measures to address the underlying issues of the conflict, the demilitarization of borders, and the concentration of all large weapons under international observation," Secretary of State Mike Pompeo said in a statement also issued on Tuesday that called for coalition air strikes to "cease in all populated areas in Yemen."

Mattis expressed hopefulness that the Saudi coalition — which also includes United Arab Emirates forces —“are ready.”

The Houthis — and their patrons in Tehran — remain a key question mark in any peace process. The UN attempted to hold peace talks in Geneva fin September but the Houthi delegation failed to appear. “If the Houthis had not walked out of the last effort, we would probably be on our way [to peace] right now,” Mattis said.

“We can’t say we’re going to do it sometime in the future. We need to be doing this in the next 30 days,” Mattis said. “We’ve admired this problem for long enough down there.”