WASHINGTON — The top American air commander in the Middle East is urging the Saudi-led coalition of Arab nations to be more forthcoming about an investigation into an airstrike in northern Yemen earlier this month that struck a school bus, killing more than 40 children.
The comments by Lt. Gen. Jeffrey L. Harrigian reflected increasing exasperation by United States officials over the conflict that has spiraled into a humanitarian disaster.
“There’s a level of frustration we need to acknowledge,” General Harrigian said in a wide-ranging telephone interview last week. “They need to come out and say what occurred there.”
His comments were the latest, and bluntest, public critique of the Saudi-led air campaign against Houthi rebels that have been voiced by a growing number of senior American military, Pentagon and diplomatic officials seeking to distance the United States from the conflict — but who are facing increasing questions about American support for the air war with every errant strike.
The United Nations condemned a separate airstrike south of the contested port city of Hodeida on Thursday that relief officials said killed 27 civilians, including 22 children. “What is happening in Yemen is unthinkable,” said Lise Grande, the United Nations’ humanitarian coordinator in the country.
General Harrigian is a former F-22 fighter pilot who is stepping down this week after two years commanding American air operations in the Middle East and Southwest Asia from his headquarters in Qatar. He has played a personal role in trying to persuade — and sometimes cajole — Saudi officials overseeing the air campaign to develop targeting procedures to avoid civilian casualties.
The general would not speculate how or why the school bus was struck, saying that was the focus of the ongoing investigation. “Clearly, we’re concerned about civilian casualties, and they know about our concern,” General Harrigian said, frustration edging his voice. “The key here is to take appropriate action.”
General Harrigian’s remarks echoed those of another senior American officer, Lt. Gen. Michael X. Garrett, the head of United States Army forces in the Middle East. He was directed by Defense Secretary Jim Mattis two weeks ago during a visit to Riyadh, the Saudi capital, to urge officials there to carry out a detailed inquiry into the school-bus bombing.
“He pressed the Saudis to devote the resources and oversight required to do a thorough and complete investigation and release the results to the public,” said Lt. Cmdr. Rebecca Rebarich, a Pentagon spokeswoman.
Yemen’s conflict began in 2014 when Houthi rebels, who are aligned with Iran, seized control of the capital, Sana, and sent the government into exile. In March 2015, Saudi Arabia — Iran’s chief rival for power and influence in the Middle East — formed a coalition of Arab nations and launched a military intervention to Yemen’s government. It has so far failed to do so.
Since 2015, the United States has provided the Saudi-led air campaign in Yemen with midair refueling, intelligence assessments and other military advice. American advisers say they do not give direct or indirect approval on target selection or execution of bombings. Rather, they give advice on targeting procedures and facilitate checks of a list of “no-strike” buildings, like mosques and marketplaces.
Gen. Joseph L. Votel, the head of the Pentagon’s Central Command, acknowledged in congressional testimony in March that the United States military does not track where American-refueled Saudi jets are going, what targets they strikes or the results of those missions.
The Aug. 9 attack was particularly stunning, even for a war in which children have been the main victims. The United Nations has called the suffering as among the world’s worst humanitarian crises, with rampant malnutrition and outbreaks of cholera. The war had killed more than 10,000 people before the United Nations stopped updating the death toll two years ago.
Human rights organizations say the United States cannot deny its role, given that it has approved the sale of billions of dollars in weaponry to allied coalition countries.
Congress has shown increasing concern about the war recently. A defense policy bill that President Trump signed this month included a bipartisan provision that requires Secretary of State Mike Pompeo to certify that Saudi Arabia and its close ally the United Arab Emirates are taking steps to prevent civilian deaths. Without the certification — or unless a national security waiver is invoked — the legislation bars the American refueling of coalition jets.
In the wake of the bus attack, individual lawmakers have gone further, calling on the Pentagon to clarify its role in airstrikes on Yemen and investigate whether the support for those attacks could expose American military personnel to legal jeopardy, including for war crimes.
Human rights groups say this congressional pressure is important because they have little confidence the coalition can investigate its own mistakes.
In a report last week, Human Rights Watch analyzed 17 of 75 reported incidents involving civilians deaths that the coalition says it is investigating. It concluded that international standards regarding transparency, impartiality, and independence were not met.
The Saudi-led coalition says it works to avoid civilian casualties and accuses its enemies, the Houthis, of using civilians as human shields.
An important decision for senior American officers and policymakers going forward, General Harrigian said, will be whether to increase Washington’s involvement in the campaign in hopes of preventing civilian casualties. “Do you lean in more or stay with what we’ve got now?” said the general, who is heading to a new assignment in Europe.
Writing this month on the website of the Washington Institute for Near East Policy, Michael Knights, a fellow at the institute, recommended the United States offer Saudi Arabia more assistance in defending against ballistic missile strikes, anti-ship attacks and strengthening its borders with Yemen. In exchange, Mr. Knights proposed, the Saudi-led coalition suspend all strikes against civilian locations and suspected Houthi leaders.
During his two-year command, General Harrigian has overseen some of the American military’s most demanding air operations. They have included airstrikes supporting allied ground forces toppling the last two major Islamic States strongholds — Mosul in Iraq and Raqqa in Syria — and confronting an aggressive Russian air campaign in eastern Syria backing the government of President Bashar al-Assad.
Human rights groups have criticized the American-led air campaign against the Islamic State for not thoroughly investigating its own airstrikes in Mosul and other attacks in which civilians were killed.
As the Islamic State lost much of the territory it seized in Iraq and Syria, General Harrigian redirected much of the air campaign to combat insurgents in Afghanistan. Earlier this year, commanders predicted that a new surge of American airstrikes and Afghan ground raids aimed at destroying a string of Taliban drug labs in southern Afghanistan would throw the group’s regional narcotics operations into financial disarray.
The Taliban was operating 400 to 500 labs across the country to sustain the group’s $200 million-a-year opium trade. The drug money accounted for at least 60 percent of the Taliban’s income, and went to buy weapons, recruit and pay fighters and conduct operations, American officials said.
General Harrigian acknowledged that the results have been mixed. While bombing drug labs has had some impact on the Taliban’s effectiveness, he said that “it’s probably not the key piece” of a broader effort to put pressure on the Taliban.
Shuaib Almosawa contributed reporting from Sana, Yemen.