|Abu Mansoor al-Amriki said his life is in danger due to differences with other al-Shabab commanders [YouTube]
A US-born Islamist fighter viewed as a key foreign leader within Somalia's al-Shabab group has said he fears his life is now in danger from fellow extremists.
Omar Hamami, better known as Abu Mansoor al-Amriki, gave the warning in an undated video posted on several Somali websites and YouTube on Saturday.
"To whomever it may reach from the Muslims, from Abu Mansoor al-Amriki, I record this message today because I feel that my life may be endangered by Harakat Shabab al-Mujahideen due to some differences that occurred between us regarding matters of the Sharia and matters of the strategy," he said, speaking in English.
The bearded Amriki, dressed in a black robe and with a checked scarf, posed in front of the al-Shabab's black flag and beside an automatic rifle in the minute-long video, but did not provide a location.
He provided no further details about the threats or differences with other al-Shabab commanders.
The video adds weight to reports of growing divisions within the al-Qaeda-linked al-Shabab, who face pressure on three fronts by regional and pro-government forces. Al-Shabab aims to depose the weak, US-backed Transitional Federal Government in Somalia and impose Islamic law.
Amriki had previously been seen as a key leader for foreign fighters in al-Shabab, alongside top Somali commanders Muktar Robow and Sheikh Hasan Dahir Aweys.
Some suggest Somali al-Shabab fighters view the foreign gunmen as a liability, even as potential spies, while missile strikes have targeted the foreign extremists.
However, al-Shabab spokesmen dismissed Amriki's concerns in messages posted Saturday on internet website Twitter.
"We assure our Muslim brothers that Al-Amriki is not endangered by the mujahideen, and our brother still enjoys all the privileges of brotherhood," they wrote.
"A formal investigation is just underway and HSM [Shabab] is still attempting to verify the authenticity as well as the motivations behind the video," the post added.
Alabama-born Amriki, who has reportedly been based in restive Somalia since late 2006 and is wanted by the United States on terrorism charges, has issued previous videos calling for foreign recruits, including singing rap songs praising jihad.
The Royal United Services Institution, a security think-tank, estimates that there are around 200 foreign fighters in the ranks of al-Shabab. African Union military commanders have said they have reports some are fleeing Somalia for Yemen.
Al-Shabab last month lost control of their strategic base of Baidoa to Ethiopian troops and pro-government Somali forces, the second major loss for the rebels in six months after the majority pulled out of the capital Mogadishu.
However, experts warn that al-Shabab fighters are far from defeated and remain a major threat, especially now they have switched to guerrilla tactics in many areas after leaving fixed fighting positions.