NAIROBI, Kenya (AP) — At least two people were killed and more than 20 others wounded when a suicide car bomber targeted a construction site along a highway outside Somalia's capital, police said Saturday.

Six Turkish nationals were among the wounded, with two in serious condition, Turkish Health Minister Fahrettin Koca said.

The Turkish construction workers appeared to be the bomber's target, Somali police Col. Abdi Abdullahi said.

Most of the casualties were police officers providing security for the Turkish workers constructing a highway between the capital, Mogadishu, and the agricultural town of Afgoye, 30 kilometers (18 miles) north of the city.

The al-Qaida-linked al-Shabab extremist group, based in Somalia, claimed responsibility for the attack, according to the the group's radio arm, Andalus. Al-Shabab often carries out such attacks in and near Mogadishu.

Turkey has invested heavily in Somalia, with technical and development assistance exceeding $1 billion, according to the Turkish government. Turkish companies run the international airport and seaport in Mogadishu, and in 2016 the Turkish president inaugurated Turkey's largest embassy complex in the world there.