ABUJA, Nigeria-- The U.N. says one more staff member has died nearly two months after a car bombing hit its Nigeria headquarters, bringing the death toll to 24.

Spokesman Kelechi Onyemaobi said Wednesday that Sunday Nwachukwu, who worked for The United Nations Development Program, died in South Africa on Sunday.

He said Nwachukwu was one of 12 U.N. staff members who was flown on life support to South Africa for treatment after the Aug. 26 attack. Onyemaobi could not immediately comment on the others' conditions.

A radical Muslim sect locally known as Boko Haram claimed responsibility for the blast that wounded 116 people. It was the group's first suicide attack targeting foreigners.

Boko Haram has reported links to al-Qaida and wants to implement a strict version of Shariah law in the nation.