LAGOS, Nigeria -- Royal Dutch Shell PLC says it has shut down a pipeline in Nigeria's oil-rich southern delta after finding leaks it blamed on oil thieves. In a statement Sunday, Shell said its Nigerian subsidiary shut down the Imo River trunk line which had six "theft points." It said the shutdown of the line would cut production by about 25,000 barrels of oil a day. Shell said sabotage has been responsible for 25 of 26 spills on the Imo River this year, which released nearly 3,000 barrels into the river and other waterways. Shell produced about 800,000 barrels of oil a day in Nigeria last year. Militancy in the region has dropped off after a government-sponsored amnesty program in 2009. However, violence, kidnappings and crude oil thefts still occur.