Two suicide bombers detonated explosives-laden cars on Tuesday close to a peacekeeping base and the airport in Somalia's capital, killing 13 people including seven checkpoint guards.
The attacks took place near the African Union Mission in Somalia (AMISOM) base in Mogadishu, Somali police chief Gen. Mohamed Sheikh Hassan said at a press conference.
Somali terror group al Shabaab, which wants to establish an Islamic emirate, told Al Jazeera it had carried out the attack. NBC News could not immediately verify that claim.
The first suicide car bomber tried to speed through a barrier outside the U.N.'s mine clearing office but private security guards shot at the car, Hassan said.
A second suicide blast targeted a checkpoint manned by Somali security forces near the AMISOM base. Casualties there remain unclear.
More than 22,000 troops and police serve in the African Union force, which also includes troops from Burundi, Djibouti, Kenya, Sierra Leone and Ethiopia. Al-Shabaab opposes the presence of foreign troops in Somalia and has launched attacks in countries that have contributed to the AU force.
Writer and photographer Sakariye Cismaan, who lives in a residential zone close to the airport, said his house was covered in dust and from the explosion, and a small rock.
"I heard one massive blast, followed by another one few minutes later," he told NBC News. "I spoke with a friend who works at the airport. He told me that a few friends of his are hurt by stray glass from exploded car and the airport's windows."
The AMISOM base was previously infiltrated by al Shabaab in December 2014.
The U.S. condemned Tuesday's attack as "cowardly" and sent condolences to AMISOn soldiers and their families.
"The United States stands squarely with Somalia and our partners in the fight against despicable acts of terrorism that seek to destabilize Somalia. We remain committed to helping Somalia progress along a path towards peace and prosperity and the defeat of terrorist groups, including al-Shabaab," said National Security Council spokesman Ned Price.