Nigerian President Muhammadu Buhari Image Credit: Wolfgang Kumm/picture-alliance/dpa/AP Images

Abuja: Nigerian President Muhammadu Buhari was sworn in for a second term in power on Wednesday, promising again to tackle crippling security threats and end rampant corruption in Africa's key economy.

"I do solemnly swear that I will be faithful and bear true allegiance to the Federal Republic of Nigeria," Buhari said, dressed in simple white robes and traditional embroidered cap. "I will preserve, protect and defend the constitution."