New sources say that a U.S.-led coalition raid in eastern Syria killed 32 members of the Islamic State group, also known as ISIS or ISIL, including four of its leaders. The rate is higher than the initial numbers reported by the U.S. State Department and most media sources.

The Syrian Observatory for Human Rights, a monitoring group based in Britain, reported the new numbers on Sunday, along with details about the leaders who were killed. The group reported that three out of four were Moroccan, and one of them was an assistant to Abo Omar al-Shishani, the Islamic State group’s military chief.

U.S. officials reported earlier that the action also killed Abu Sayyaf, a Tunisian Islamic State group leader who oversaw black-market oil sales and fundraising efforts was among those killed. It also said about “a dozen” fighters were killed.

“Last night, at the President’s direction, U.S. personnel based out of Iraq conducted an operation in al-Amr in eastern Syria to capture an ISIL senior leader known as Abu Sayyaf and his wife Umm Sayyaf,” National Security Council spokesperson Bernadette Meehan said in a statement. “During the course of the operation, Abu Sayyaf was killed when he engaged U.S. forces.”

Meehan also reported that no U.S. personnel were killed during the operation, and that troops freed a Yezidi woman who seemed to have been held as a slave at the Sayyaf household. The woman would be reunited with her family “as soon as feasible,” Meehan added. 

U.S. Secretary of Defense Ashton Carter said the operation was a “significant blow,” to the Islamic State, according to Agence France-Presse. Other officials emphasized the importance of putting pressure on the group’s financial resources, which are substantial.

The raid took place at night late Friday. Delta Force operators also took Sayyaf’s wife, Umm, who reportedly has high-level knowledge about the group and has been involved in human trafficking for the group. The raid also recovered laptops and other materials that should provide more insights into the Islamic State group’s inner workings.

“This is very useful, very important intelligence that we were able to collect,” a defense official told Politico.