U.S. airstrikes targeting Houthi militants in Yemen between late 2023 and mid-2025 resulted in the deaths of at least 213 civilians, according to a report released Thursday by the Costs of War Project at Brown University. The majority of civilian casualties—208 deaths and 341 injuries—occurred during the Biden administration’s tenure, as it responded to attacks by the Iran-backed group on maritime targets in the Red Sea.
The report highlights a series of retaliatory strikes ordered by President Joseph R. Biden Jr. following Houthi attacks on a Navy destroyer in October 2023, and subsequent missile and drone assaults on civilian vessels in January 2024. These operations continued up to several weeks prior to Biden leaving office. In March 2025, under President Donald Trump’s administration, the Pentagon launched a campaign known as Operation Rough Rider in response to further Houthi attacks on commercial shipping.
Two strikes in particular bore heavy civilian tolls. On April 17, 2025, U.S. forces killed an estimated 80 civilians during a strike on a port facility in the Houthi-controlled Hudaydah province. Less than two weeks later, an attack on warehouses used to detain African migrants resulted in 68 civilian deaths. According to the report, many of those killed were primary income earners for their families, exacerbating poverty and homelessness in communities already facing severe humanitarian challenges.
Stephanie Savell, an anthropologist and director of the Costs of War Project, emphasized the broader impact beyond immediate casualties. “The report looks precisely at civilian infrastructure that’s targeted, not military infrastructure or outposts,” she said, underscoring the indirect human costs related to the destruction of farms, shops, factories, and small businesses.
The Pentagon has not publicly confirmed civilian deaths from the 2024 strikes but reported 153 civilian deaths and 243 injuries in Yemen in 2025. A Defense Department report acknowledged civilian fatalities from the strikes on the Hudaydah port, the migrant detention facility in April 2025, and an April 6 strike in the capital Sanaa, which killed five civilians and wounded 25. However, it stated that condolence payments to affected families were deemed “not appropriate” in these cases.
The report also notes that in early 2025, the U.S. Army significantly reduced staffing for an office dedicated to minimizing civilian harm, cutting its personnel from around 200 to 11. The Defense Department did not respond to requests for comment on this staffing change or the report’s findings.
Former State Department attorney Brian Finucane, who advised on the law of war, stated that civilian casualties during the Rough Rider campaign were “more significant” than in previous Biden administration attacks. He also noted that the Trump administration conducted two to three times the number of strikes as Biden did and targeted more densely populated areas. Finucane criticized the attack on the migrant detention facility, which he said was routinely monitored by Red Cross officials and should have been recognized as off-limits.
From December 2023 to January 2025, the Pentagon conducted approximately 930 airstrikes against the Houthis. Operation Rough Rider, initiated in March 2025 under Defense Secretary Pete Hegseth, incurred costs exceeding $1 billion before being halted by President Trump on May 5, 2025, amid frustration over the campaign’s limited progress.
The Costs of War Project collaborated with Mwatana for Human Rights, a Yemen-based organization, to gather evidence through interviews, analysis of weapon remnants, and documentation such as death certificates. The findings contribute to an ongoing assessment of the human toll resulting from U.S. military operations in Yemen against the Houthis, who are part of the regional “axis of resistance” linked with Iran alongside Hezbollah and Hamas.