WASHINGTON — The United States this week killed a top Islamic State commander in Syria as part of a spate of military actions targeting the terrorist group's leadership and explosives caches, Defense Secretary Ash Carter said on Friday.
The killing of a top commander, Abd al-Rahman Mustafa al-Qaduli, who is also known by other names, comes as the United States is having increased success targeting the Islamic State's leadership. Last week, Defense Department officials concluded that U.S. strikes had killed the group's minister of war, Omar al-Shishani.
"We are systematically eliminating ISIL's cabinet," Carter said at a news conference, using an acronym for the group.
But he made clear that the challenge was not that simple.
"Striking leadership is necessary," he said, "but as you know it's far from sufficient. As you know leaders can be replaced. These leaders have been around for a long time — they are senior and experienced and eliminating them is an important objective and result. They will be replaced and we will continue to go after their leadership."
Carter said Qaduli was the Islamic States's finance minister and was responsible for planning some of its attacks abroad. Carter said he did not know whether he had played a role in the bombings this week in Brussels.
"The removal of this ISIL leader will hamper the organization's ability for them to conduct operations both inside and outside of Iraq and Syria," he said.
The military also targeted a senior Islamic State leader known as Abu Sarah who is in charge of paying the group's fighters in northern Iraq, Carter said. He said U.S. airstrikes had also destroyed "a significant quantity of improvised explosive devices and bomb-making equipment" that could have been used against Iraqi forces as they try and reclaim the city of Mosul.
Defense Department officials have declined to elaborate why they are having more success striking the groups top commanders. Earlier this year, a special unit of U.S. commandos tasked with identifying, capturing and killing the Islamic States leaders arrived in Iraq and began working closely with local forces there.
"The momentum of this campaign is clearly on our side," Carter said.
A similar group of U.S. special forces in Syria has been working alongside rebel groups there for several months.
Despite the victories on the battlefields in Iraq and Syria, the Islamic State still appears capable of pulling off large, complex attacks far beyond its safe haven. This week, the group claimed credit for the bombings in Brussels that killed 31 people and injured scores.