Former Nigerian President Muhammadu Buhari, who led the country twice as a military head of state and a democratic president, has died aged 82.

Nigeria's former President Muhammad Buhari was buried on Tuesday in the backyard of his home in northern Katsina state, as residents climbed trees to bid farewell to the 82-year-old.

Buhari - pictured here in 1977 with the then-King of Sweden Carl XVI Gustaf and Saudi Arabia's Sheikh Ahmed Zaki Yamani in 1977 - began his military career straight out of school. By the time this picture was taken, Buhari had risen to become a regional military commander.