Somali insurgent group Hizbul Islam seized the pirate haven of Haradheere on Sunday without a fight and pledged to take control of more towns in the region, the rebel group said.
Here are some key facts about the group:
* The group was founded on Feb. 4, 2009. Hizbul Islam is an umbrella organisation of four groups led by cleric Sheikh Hassan Dahir Aweys, who has been an influential figure among Islamists.
* The four groups' leaders had previously participated in the Union of Islamic Courts administration of Somalia in 2006. The Islamists ruled the capital Mogadishu and much of Somalia in 2006, until they were defeated in Dec. 2006 by Ethiopian troops and Somali government forces. The Islamists have since regained control of much of the territory from which they were expelled.
* Following the military withdrawal of Ethiopia from Somalia in early 2009 and the election of President Sheikh Sharif Ahmed, the four groups united with the aim of replacing Ahmed's government with a hardline Islamic state.
* Aweys is among more than 180 individuals or entities the United States "linked to terrorism" shortly after the Sept. 11 attacks, freezing their assets.
* President Ahmed, himself a former Islamist rebel, had hoped to bring members of Hizbul Islam into his administration after being elected president. There have been a number of attempts to negotiate, but Aweys has refused to join.
* Hizbul has carried out attacks with the main insurgent group -- al Qaeda-linked al Shabaab -- notably in Feb. 2009 in an attack on Mogadishu which killed over 80 people.
* More than 21,000 civilians have been killed in Somalia since the insurgency started in 2007.
* While Hizbul Islam and al Shabaab have fought together against the government in Mogadishu, they are rivals in other parts of the country. The two groups have fought over the southern port of Kismayu, which is now under al Shabaab.
* Over the past year, al Shabaab is perceived to have become more powerful than Hizbul Islam and controls more territory.
* In recent months, Hizbul Islam has taken a harder line than in the past, shifting more towards al Shabaab, which wants to impose its own harsh version of sharia law in Somalia.
* Last month, Hizbul Islam expressed its loyalty to al Qaeda for the first time and invited leader Osama bin Laden to the Horn of Africa nation.
* In Dec. 2009 the rebels executed two men for adultery and murder. It was the first time Hizbul Islam guerrillas had executed people in the type of punishment usually associated with the more hardline al Shabaab group.
* There is also some suspicion that two rare attacks on mosques in the capital this week were the result of infighting between insurgent groups seeking to gain the upper hand.
* A landmine killed one person outside a mosque on Tuesday and nearly 40 worshippers were killed on Saturday by two explosions in another mosque nearby.