In a statement released Monday, the group said Abu Mansour al-Amriki does not represent al-Shabaab or speak for it, Shabelle Media Network reported. His Internet statements have given the news media the false impression of divisions within al-Shabaab, the group said.
"The opinions expressed by Abu Mansour, the alleged frictions and the video releases are merely the results of personal grievances that stem purely from a narcissistic pursuit of fame and are far removed from the reality on the ground," al-Shabaab said.
Al-Amriki was born Omar Hammami in the Mobile, Ala., area. He formerly played a key role in convincing U.S. residents who were born in Somalia or had ties to the country to join al-Shabaab, CNN reported.
He posted two videos in March and October that suggested differences with the group.
"I feel that my life may be endangered by Harakat Shabaab al-Mujahideen due to some differences that occurred between us regarding matters of the sharia and matters of strategy," he said in the first one.
In the second, he urged Islamist leaders to intervene in Somalia, saying there was a rift between foreign fighters and Somali militants.