Omar Hammami, an Alabama-native turned designated terrorist leader of the Somali terrorist group al-Shabaab, was reported to have been executed by fellow commanders, according to unconfirmed reports posted Friday on the website of Mobile NBC affiliate WPMI-TV15.

Hammami, aka Abu Mansour al-Amriki, posted a YouTube video last month in which he told viewers that he feared for his life because of differences within his group over "matters of Shariah and matters of strategy." He did not elaborate on the controversy that allegedly put him at odds with the al-Shabaab leadership.

For its part, al-Shabaab claimed to pose no threat to Hammami, who joined the group in 1999.

The reports of his killing are yet to be confirmed by NBC News or by al-Shabaab's press office.