Akume is not a controversial figure

George Akume, governor of Benue state in central Nigeria, was in a convoy of cars when gunmen burst out of the hills and opened fire, targeting his car.

He was unhurt but shaken after his friend died next to him.

Last month, another prominent Nigerian politician was shot dead, raising fears of a return to the days when political assassinations were relatively common.

Sirens blaring

There was apparently no attempt to steal anything from the convoy, which was travelling with its sirens blaring, so armed robbery does not appear to be a motive for the shooting.

The ambush occurred near the village of Nassarawan Eggon, 150km south-east of the capital Abuja at 0700 local time (0600GMT) on Wednesday morning.

The BBC's Mannir Dan Ali says that Mr Akume, from the ruling People's Democratic Party, is not a particularly controversial politician.

However, he did criticise the government over its handling of the army's shooting of some 200 civilians in Benue state in 2001.

Benue is one Nigeria's most ethnically diverse states and the army was accused of taking sides in clashes between the rival Jukun and Tiv groups.

Senior PDP official Aminasoari Dikibo was shot dead in the volatile Delta state last month.

Reuters news agency reports that some 15 prominent politicians have been killed since military rule ended in 1999.