The former rebel commander took the oath in the grounds of the presidential palace.

"I swear allegiance to the republic of Sudan," said Kiir, who from 1983 until a peace treaty in January had fought against the Khartoum government for autonomy for Sudan’s southern people.

Afterwards Kiir, President Omar el-Bashir and Second Vice President Ali Osman Mohammed Taha stood for photographs. The ceremony was witnessed by hundreds of people, including foreign ambassadors.