Hundreds of civilians have been killed in al-Shabab's bloody war against the government [AFP]

The anti-government group al-Shabab is fighting to overthrow the Somali government and controls most of the capital, Mogadishu. Hundreds of civilians have been killed in attacks by the group and in the crossfire between its fighters and government troops. 

The group was formerly the military wing of the deposed Islamic Court Union (ICU) that controlled much of central and southern Somalia in late 2006.

These are some of the key events in the group's recent history.

June-July, 2006: The Islamic Courts Union, an umbrella organisation of local sharia courts, takes over Mogadishu after heavy fighting with warlords. It becomes an alternative to the internationally recognised transitional government.

December, 2006-January, 2007: Troops from neighbouring Ethiopia intervene against the Islamic Courts and in support of the weak central government.

Islamic Courts leaders flee but the movement's youth military wing, al-Shabab, stays to fight and chaos returns to the capital Mogadishu.

March 6: The first units of an African Union (AU) force begin arriving in Mogadishu, amid heavy fighting.

October 26, 2008: The government and moderate fighters reach an agreement on a ceasefire and the progressive withdrawal of Ethiopian forces.

January 2009: The last Ethiopian troops pull out of the country. Sharif Ahmed, the former leader of the Islamic Courts, is elected Somalia's new president by parliament.

April 18: Parliament endorses a plan to introduce Islamic law, sharia, which was a key demand by anti-government groups for their co-operation with the government.

May 7: The beginning of a major offensive by al-Shabab and Hizbul Islam, another anti-government group, aimed at overthrowing the president.

September 17: A double suicide attack on the AU force in Mogadishu, claimed by al-Shabab, kills 21, including 17 African  soldiers.

January, 2010: More than 250 civilians are killed over the month in fighting between government forces and fighters in the centre of the  country.

July 12: Al-Shabab claims responsibility for bombings in the Ugandan capital Kampala that killed 76 people, after the movement warned that Uganda would face retaliation for contributing to the AU force.

July 25-27: African countries pledge 4,000 extra troops to the African Union's force, which previously had about 6,000 troops from  Uganda and Burundi.

August 24: Two al-Shabab fighters disguised as government soldiers go on a shooting rampage in a Mogadishu hotel, killing at least 35  people, including eight parliamentarians, before blowing themselves up.