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 the $5 million bounty for Afghani, who opposed the command of top Shebab leader Ahmed Abdi Godane. Godane, who the US have offered $7 million for, earlier this month ordered the arrest of Afghani and at least a dozen other leaders, according to security sources. Shebab gunmen also killed Abul Hamid Hashi Olhayi, named as another senior commander and co-founder of the group. The deaths show the splits in the long-running insurgency to topple the internationally-backed government, but also signal Godane\'s efforts to sweep away opposition to his command and cement his more radical leadership. Family members -- including Afghani\'s sister -- 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 foreign forces from Somalia, while others -- including Godane -- have more international jihadi ambitions. However, despite its divisions, analysts say it remains a dangerous and powerful force. Earlier this month the Shebab showed their strength with a brazen daylight attack on a fortified United Nations compound in Mogadishu, with a seven-man suicide commando blasting into the complex and starting a gun battle to the death. The coordinated attack on the UN killed 11, tactics already tried in April when they attacked a Mogadishu court house. -- Somalia\'s \'Night of the Long Knives\' -- In April, a letter was circulated on extremist websites reportedly penned by Afghani to Al-Qaeda leader Ayman al-Zawahiri, criticising Godane\'s leadership. \"They disobeyed orders, and feebly tried to divide the group by issuing statements contrary to the position of the Shebab,\" Musab added. Security sources report that clashes broke out between Godane\'s troops and rival factions 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 killed, factions opposed to Godane have scattered. Veteran Islamist leader Sheikh Hassan Dahir Aweys escaped north by boat to his homeland, the autonomous Himan and Heeb region. But on Saturday, security officials in Mogadishu confirmed he had flown to the capital, where he was reported to be in talks with government officials. However, the exact terms of his position -- and how far he had voluntarily gone to Mogadishu -- were not clear. The former army colonel -- a hero of Somalia\'s 1977-78 war with Ethiopia -- is on both United States and UN Security Council terrorism sanctions lists, but no bounty has been placed on his head. Aweys, in his late 70s, was a top leader of the Islamic Courts Union, a radical group that ruled Somalia in 2006 before being overthrown by Ethiopian troops who stormed Somalia in a US-backed invasion. Washington also offers $5 million for another Afghan war veteran at odds with Godane, former Shebab \"spiritual leader\" and spokesman Mukhtar Robow, also fighting with Godane. Robow, according to unconfirmed sources, also fled Barawe and headed towards the Hudur in the southern Bakool region, a stronghold of his clan. Godane has also issued death sentences in absentia for at least a dozen foreign fighters with the Shebab. They include Alabama-born Omar Hamami -- better known as Al-Amriki or \"the American\", who also has a $5 million bounty for his arrest offered by his own government. Long active mainly in southern and central Somalia, a string of key towns have been wrested from the Shebab by a 17,700-strong African Union force, fighting alongside government troops. But analysts warn that the divisions among the Shebab do not necessarily dent its strength. \"The evolution of the Islamist group appears to be aiming at a future objective where it might not be in charge of the country, but where it could make the country ungovernable,\" South Africa\'s Institute for Security Studies (ISS) warns.