Washington (CNN) The Pentagon confirmed Friday that a U.S. drone strike this week killed Junaid Hussain, an ISIS operative linked to the Garland, Texas, cartoon contest attack.

Centcom spokesman Col. Patrick Ryder told reporters Friday that Hussain was killed in an Aug. 24 airstrike in Raqqa, Syria, as first reported on CNN Wednesday.

Hussain, a British citizen, was a hacker who published the names and personal information of military personnel online as well as inspiring attacks like the one in Texas.

Raqqa, located in northern Syria and the self-declared capital of ISIS, has been treated as a safe haven by ISIS, some U.S. officials pointed out to CNN, so reaching him in the city adds to the significance of the strike.

Several U.S. officials told CNN that the drone strike specifically targeted Hussain traveling in a vehicle in Syria after the U.S. got intelligence on where he was and watched him to confirm his presence before striking. Subsequent assessments indicated that Hussain had stepped outside when he was hit by a missile from a U.S. drone.

Asked about the strike on Hussain Thursday, Pentagon spokesman Capt. Jeff Davis responded: "We have conducted a number of strikes over the past 72 hours in Syria, specifically at ISIL leadership."

The mission was conducted by the U.S. military because it has clear rules of engagement to attack ISIS, and there could be no implication the British government was involved in the killing of Hussain, a British citizen.

U.S. officials said there is a good deal of sensitivity about potential reaction in Muslim communities in the UK if a formal announcement is made, given that Hussain was a British citizen targeted by the U.S.

There is now a complex process underway, as there is with all strikes targeting specific ISIS members, to confirm the targeted individual was indeed killed.

This is the second strike against a senior ISIS operative in as many weeks. Last week a drone strike killed Haji Mutazz, the top ISIS deputy to Abu Bakr Al Baghdadi, head of the organization. U.S. officials said that since the Mutazz killing, ISIS leadership appears to be arresting and killing a number of people it suspects may have disclosed intelligence about the group's movements.

Hussain is described by U.S. officials as a high-value target in ISIS.

"This is a great intelligence success," one U.S. official told CNN.

Hussain is alleged to have been involved in circulating a so-called hit list of addresses and photos of U.S. military personnel put out by a group calling itself the Islamic State Hacking Division.

Hussain also was linked to the attack in earlier this year on a cartoon drawing contest in Garland, Texas, where participants were asked to draw the Prophet Mohammed. Investigators believe Hussain played a role online in private messaging to radicalize and inspire one of the gunmen to launch an attack. The gunmen were shot dead by a Garland police traffic officer who was part of the on-site security contingent at the event.

Hussain's death eliminates the most prolific of all of ISIS's English-language propagandists, according to CNN terrorism analyst Paul Cruickshank. In recent months, Hussain had used Twitter to incessantly call for attacks in the West, as well as groomed potential terrorists in Western countries over encrypted online messaging apps, such as "Surespot," Cruickshank said.