Al Shabab militants stormed a Kenyan university campus near the border with Somalia and seized Christian hostages in a predawn attack Thursday that killed at least 15 people and wounded many more. A spokesman for the Somalia-based terror group said al Shabab members were behind the deadly assault at Garissa University College and had taken non-Muslims as captives, according to Agence France-Presse. “Kenya is at war with Somalia,” al Shabab spokesman Sheikh Ali Mohamud Rage said Thursday. Below are five things to know about al Shabab.

1. Al Shabab has been designated as a terrorist organization by the United States, the United Kingdom, the United Arab Emirates, Canada and Australia. The U.S. State Department has open bounties on several of the group’s senior officials.

2. Al Shabab is linked to al Qaeda. The militant Islamist group pledged loyalty to the al Qaeda terrorist organization in 2012. Al Shabab wants to overthrow the Somali government and impose its own harsh enforcement of Shariah law in the country, according to Al Jazeera. The United Arab Emirates' top diplomat has expressed fear that al Shabab will team up with militants of the Islamic State group -- also known as ISIS or ISIL -- in Somalia, Al Arabiya reported in October.

3. Al Shabab is an offshoot of the Islamic Courts Union. The group emerged as an extreme militant youth movement from the ICU, a coalition of local Shariah courts that united to briefly govern large areas of Somalia in 2006, according to World Politics Review.

4. Al Shabab leader Ahmed Abdi Godane was killed in September 2014 by a U.S. drone strike in Somalia. Godane, also known as Moktar Ali Zubeyr, allegedly was behind the deadly attack on a Nairobi shopping mall in 2013, in which 67 people were killed. “Removing Godane from the battlefield is a major symbolic and operational loss to Al Shabab," Pentagon press secretary Rear Adm. John Kirby told CNN at the time.

5. Al Shabab has been accused of killing tens of thousands of elephants in Africa every year for their ivory. The Islamist militants also have been accused of killing park rangers hired to protect the elephants. Profits from the lucrative ivory trade have helped fund al Shabab operations, according to the Elephant Action League.