At least 10 people were killed Saturday in a U.S.-led attempt to free two foreign hostages in Yemen.
Yemeni security officials said the dead were al-Qaida militants, while local residents included a child among the deceased.
According to U.S. officials, American journalist Luke Somers and South African teacher Pierre Korkie were shot and killed by their captors as U.S. special forces raided a village in Shabwa province early Saturday.
Both men had been held hostage for more than a year.
Speaking to U.S. troops in Afghanistan on Sunday, U.S. Defense Secretary Chuck Hagel defended the rescue mission, calling the process "as thorough as there can be." A day earlier, he classified the raid as "extremely well-executed."
Senior U.S. officials have said the raid was carried out by U.S. forces alone, but both Yemen's government and local residents said Yemeni forces also participated and engaged militants holding Somers and Korkie.
Gift of the Givers, the aid group Korkie worked for, said on Saturday that the teacher's release had been negotiated before the raid. His body was expected in South Africa on Monday.
An earlier U.S. attempt to rescue Somers, a photojournalist, had also failed.
Al-Qaida in the Arabian Peninsula is one of the militant group's most active branches; along with its affiliates, AQAP is believed to make tens of millions of dollars annually in ransom for hostages.
At least one Briton and a Turkish man are still being held by the group.