He is a former military dictator who briefly seized power in the 1980s and now says he regrets his ruthless past. Spare in charisma and physique, Nigerian President Muhammadu Buhari faces new pressure to deliver after securing a second term in Africa’s most populous nation.

The 76-year-old Buhari won Saturday’s election despite frustration with what many people have called a slow, insufficient approach to tackling corruption, insecurity and the economy. As he neared victory, the Nigerian Stock Exchange dipped as investors who had banked on a more business-friendly challenger got out.

The president is seen as unusually upright and reserved in this vibrant country of some 190 million people, where gregarious politicians spend heavily to secure lucrative posts — often becoming ensnared in graft.

FILE - In this Saturday, Feb. 23, 2019 file photo, Nigeria's President Muhammadu Buhari gestures to supporters after casting his vote in his hometown of Daura, in northern Nigeria. (AP Photo/Ben Curtis, File)
FILE – In this Saturday, Feb. 23, 2019 file photo, Nigeria’s President Muhammadu Buhari gestures to supporters after casting his vote in his hometown of Daura, in northern Nigeria. (AP Photo/Ben Curtis, File)
Street-vendors and others walk past a billboard showing Nigeria's President Muhammadu Buhari and other party officials, in Kano, northern Nigeria Tuesday, Feb. (AP Photo/Ben Curtis)
Street-vendors and others walk past a billboard showing Nigeria’s President Muhammadu Buhari and other party officials, in Kano, northern Nigeria Tuesday, Feb. (AP Photo/Ben Curtis)
In this photo released by the Nigeria State House, Nigeria Incumbent President Muhammadu Buhari, left, listen to Director of Election Planning and Monitoring Babatunde Raji Fashola, right, as he explain the progress of the party election results in Abuja, Nigeria Monday, Feb. (Bayo Omoboriowo/Nigeria State House via AP)
In this photo released by the Nigeria State House, Nigeria Incumbent President Muhammadu Buhari, left, listen to Director of Election Planning and Monitoring Babatunde Raji Fashola, right, as he explain the progress of the party election results in Abuja, Nigeria Monday, Feb. (Bayo Omoboriowo/Nigeria State House via AP)