Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

Ahmed Abdi Godane — the leader of al Shabab, the Islamic militant organization behind the siege on a mall in Kenya last year — was killed in a U.S. military strike earlier this week, an al Shabab source told NBC News on Friday.

The Pentagon confirmed the death later in the day.

“Removing Godane from the battlefield is a major symbolic and operational loss to al Shabab,” said Rear Adm. John Kirby, a Pentagon spokesman. “The United States works in coordination with its friends, allies and partners to counter the regional and global threats posed by violent extremist organizations.”

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

A U.S. security official also told NBC News earlier in the week that Shabab had been killed by the strike on Monday. U.S. officials had said publicly after the strike that Godane was targeted, but that they were not sure whether he was dead.

The al Shabab source told NBC News that Godane was among 11 militants killed. Also killed were an operations leader, a financial official and a military strategist for the organization, the source said.

“It’s a big win,” the U.S. security official said. “He was operationally savvy and ideologically driven, with aspirations off the charts.” The official said that nine Hellfire missiles and one 500-pound guided bomb had been used in the strike.

The Reuters news agency reported Friday that the Somali prime minister had confirmed the death on Facebook, but Reuters later withdrew that report. A Somali government spokesman told Reuters that the government had not yet commented on whether Godane was dead.

The siege last September at the Westgate Mall in Nairobi left 67 people dead and about 200 injured.

The United States in 2012 offered a $7 million reward for his arrest. Godane took leadership of al Shabab after his predecessor was killed in an American airstrike in 2008.

IN-DEPTH

— Richard Engel, Charlene Gubash and Erin McClam