Gangs of jobless youth make money from kidnapping and extortion
An 11-year-old girl has been shot dead as she tried to prevent militants kidnapping her brother in Nigeria's oil-producing Niger Delta region.
The armed men seized the boy as the two walked to school in Port Harcourt, capital of Rivers State.
The children's father works for Royal Dutch Shell, a company spokesman said.
Earlier in the day, a Catholic priest kidnapped on Sunday was released after a militant leader told the group holding him to let him go.
Militant groups have been kidnapping oil company employees and their families since 2006 as part of a campaign that has cut oil production by some 20%.
Police named the girl as Oduayo Awonusi.
Her brother Emmanuel is nine.
"The gunmen came out of the vehicle and grabbed the boy," Rita Inoma-Abbey, police spokeswoman for Rivers State said.
"While the sister was struggling with them, she was shot. The gunmen went away with the boy. Passers-by rushed the girl to hospital but she died on the road."
Some militant groups say they are fighting for a fairer share of Nigeria's oil wealth.
But other gangs of armed, jobless youths have made money through kidnapping, extortion and oil theft.
In 2007 militants kidnapped three-year-old Margaret Hill, the child of a British bar-owner in Port Harcourt.
She was released without harm, but her father Mike died shortly afterward of a heart attack.
Unidentified militants kidnapped Father Pius Kii from the steps of his church on Sunday.
It is understood that no ransom was paid for his release.