The Joint Task Force rescue operation Sunday extended from Gbaramatu to Abonnema, where Sele was shot and killed, and other militant leaders fled, the Lagos Daily Independent reported Monday.
JTF spokesman Col. Rabe Abubakar said the operation was focused on suspected havens for militant and their hideouts where hostages were being kept, not a random operation.
"With the successes recorded so far in the course of this operation, the JTF wants to debunk the allegation that its troops are targeting some individuals, or certain ethnic groups," JTF spokesman Col. Rabe Abubakar said.
The Movement for the Emancipation of the Niger Delta vowed to fight the Joint Task Force and people the group's leaders consider traitors, the Daily Independent said.
"Nobody should go home with his two eyes closed because the war has just begun," the organization said.
Militant groups in Nigeria's Niger Delta have kidnapped more than 200 foreigners since 2006, although most were released unharmed, online encyclopedia Wikipedia said.