Mogadishu, a large city on the east African nation's coast, has endured high levels of violence for years. Al-Shabaab, an al Qaeda-linked terror group, has carried out several deadly car bomb attacks.

Last August, the US State Department warned Americans to avoid traveling to Somalia because of widespread terrorist and criminal activity. The warning said al-Shabaab and ISIS "operate with relative impunity throughout large parts of the country, including Mogadishu, and attack civilian, military, and government targets."

The White House issued a statement condemning the attack, calling terrorist organizations "the enemies of all civilized people."

"The United States stands with the people and government of Somalia in their commitment to defeating these groups, ensuring the security of their people, and rebuilding their country," the statement said.