Somali Al-Shebab fighters gather on February 13, 2012 in Elasha Biyaha, in the Afgoei Corridor, after a demonstration to support the merger of Al-shebab and the Al-Qaeda network. Shebab insurgents staged rallies across Somalia on February 13 to celebrate their group's recognition by Osama bin Laden's successor as a member of the Islamist Al-Qaeda network. Al-Qaeda chief Ayman al-Zawahiri announced in a video message posted on jihadist forums on February 9, 2012 that Shebab fighters had joined ranks with the Islamist network. AFP PHOTO / Mohamed Abdiwahab (Photo credit should read Mohamed Abdiwahab/AFP/Getty Images)
Why Al-Shabaab is a growing threat (2015)
01:37 - Source: CNN
CNN  — 

At least 45 African Union and Somali national army forces died in an al Shabaab raid on their base in southern Somalia on Tuesday, western sources told CNN.

More than 100 troops were unaccounted for.

At least 20 of the troops were Ugandans taking part in the mission to hold a base in Janaale, Somalia, the sources said Wednesday.

Al Shabaab has been designated a terrorist organization by several countries, including the United States. It has waged a long insurgency in Somalia.

The extremist group has stepped up hit-and-run raids on remote bases as a tactic to fight the African Union forces seeking to break their insurgency.

What is Al-Shabaab, and what does it want?