U.S. airstrikes killed three key leaders of the Islamic State group in Syria, including two involved in last year’s attacks in Paris, U.S. Defense Secretary Ash Carter said Tuesday.

He announced the killings during an address to U.S. airmen at a military base in Italy.

“I can confirm today we took out three of ISIL’s key leaders in the last couple of weeks by one strike. These were guys linked to plots right here in Europe … for example with the Paris attacks,” Carter said, referring to the November 2015 attacks in Paris that killed 130 people.

Carter’s spokesman, Peter Cook, said later that the three were killed in an airstrike Dec. 4 in Raqqa.

Cook said the two involved in the Paris attacks, Salah Gourmat and Sammy Djedou, were close associates of Islamic State external operations leader Abu Mohammed al-Adnani, who was killed in August.

He said the third person, Walid Hamman, had been convicted in absentia in Belgium for a disrupted 2015 planned attack.

Coalition airstrikes in Iraq and Syria have been taking out an increasing number of Islamic State leaders in recent months, aided by improved intelligence gathering from forces on the ground and from troves of information collected as IS has been driven out of neighborhoods.

Asked at a news conference later about the Islamic State’s ability to quickly replace leaders and operatives who are killed in U.S. airstrikes, Carter said his announcement Tuesday was a reminder that U.S. counter-IS operations are aimed at protecting the American homeland.

“We remained focused on, and are consistently operating against, those who intend to conduct attacks upon the United States,” he said. “That’s an important priority. That is the priority the president gives us.”

Carter also said that with the elimination of the final pocket of IS resistance in the Libyan city of Sirte, the U.S. has “concluded” its support to the Government of National Accord in its lengthy effort to regain control of that coastal city.

“That doesn’t eliminate ISIL from Libya,” he said, using an alternative acronym for the militant organization. “Sirte was their most important single nest and stronghold in Libya, but as it appears other places, we are prepared to take action.”

(AP)