Updated

Somalia's Al-Qaeda-linked Shebab extremists have killed two of their own top commanders, one with a $5 million United States bounty on his head, the insurgents said Saturday.

"We have informed their widows of their deaths, as they must now wear the clothes of mourning," Shebab spokesman Abdulaziz Abu Musab told AFP.

The pair killed are two co-founders of the Islamist group, including US-wanted Ibrahim Haji Jama Mead, better known by his nickname Al-Afghani -- "the Afghan", due to his training and fighting with Islamist guerrillas there.

Washington offered a $5 million bounty for Afghani, who opposed the command of top Shebab leader Ahmed Abdi Godane.

Godane earlier this month ordered Afghani and other leaders' arrest.

Shebab gunmen also killed Abul Hamid Hashi Olhayi, named as another senior commander and co-founder of the group.

Family members said they were arrested and then executed, but the Shebab said they were killed during a gun battle.

"We deny reports that the men were killed after capture," Musab told AFP.

"The two men were killed in a shoot out when they were resisting arrest on court orders."

Somalia's Shebab is fractured into multiple rival factions, some based along clan lines and others ideological.

Some are more attracted by a nationalist agenda to oust foreigners from Somalia, while others -- including Godane -- have more international jihadi ambitions.

However, despite its divisions, analysts say it remains a dangerous and powerful force.

Afghani formerly headed the extremist group's forces in southern Somalia's Lower Juba region, based in the strategic port city of Kismayo.

In April, a letter was circulated on extremist websites reportedly penned by Afghani to Al-Qaeda leader Ayman al-Zawahiri, criticising the leadership of Godane.

Security sources report that clashes broke out between Godane's troops and forces loyal to Afghani on June 20 in the southern Somali port of Barawe, one of the few towns still held by the Al-Qaeda-linked insurgents.

After the fighting in Barawe in which Afghani was captured, factions opposed to Godane have scattered.