A Nigerian militant group says at least 10 of its fighters have been killed in a clash with Nigerian soldiers.
The Movement for the Emancipation of the Niger Delta says Nigerian government troops in gunboats ambushed a group of its fighters late Sunday.
The ambush was in Baylesa state, in the oil-rich delta region.
Nigerian President Olusegun Obasanjo announced a clampdown on Niger Delta militants last week, after a series of kidnappings of foreign oil workers.
The kidnappings and attacks on oil facilities have caused a 20 percent drop in Nigeria's oil production since February.
Nigeria's army said Saturday that more than 100 militants had been detained in a military sweep.
Some information for this report was provided by AP and Reuters.