May 21, 2007
Fatah al-Islam emerged in November 2006 when it split from Fatah al-Intifada (Fatah Uprising), a Syrian-backed Palestinian group based in Lebanon.
Dozens of people died in clashes between the group and Lebanese government forces that started on 20 May.
Fatah al-Islam is believed to have between 150 and 200 armed men, all in Nahr al-Bared refugee camp north of Tripoli.
Palestinian refugee camps in Lebanon are often a haven for armed groups. Lebanese security forces do not enter the camps, only guarding their perimeters.
The Lebanese government has linked Fatah al-Islam to the Syrian intelligence services. Syrian officials and Fatah al-Islam deny the connection.
The Beirut government says four Syrian members of Fatah al-Islam were arrested and confessed to the twin bus bombings in February that killed three people in a Christian area near the capital.
The members of the group are believed to be from mixed national origin, but a Lebanese minister has said that "many" of them are Lebanese.
Fatah al-Islam is led by Shakir al-Abssi, a well-known Palestinian militant.
Abssi was sentenced to death in absentia in Jordan for killing a US diplomat, Laurence Foley, in Amman in 2002.
Abu Musab al-Zarqawi, the leader of al-Qaeda in Iraq who was killed in 2006, was also sentenced to death for the killing of Foley.
Abssi has said that his group has no organisational links to al-Qaeda, but agrees with al-Qaeda's ideology of fighting and killing non-Muslims.
Fatah al-Islam's statements have appeared on Islamist web sites known for publishing al-Qaeda statements.
Abssi told the Reuters news agency recently that his group had two main aims: Islamist reform of the Palestinian refugee community in Lebanon in line with Islamic Sharia law, then confronting Israel.
His group also aims to drive Americans and their interests out of the Islamic world.
Security experts point to Fatah al-Islam as one of a range of armed Islamist groups independent of al-Qaeda in terms of logistics and finances, but sharing al-Qaeda's aims and ideology.