Nigeria's task force has freed four Ukrainian hostages and destroyed another key camp of the major militant group in the southern Niger Delta region, the military told Xinhua on Monday.
The military has released 17 hostages since launching Operation Restore Hope on Wednesday, including nine Filipinos, four Nigerians and four Ukrainians.
Military spokesman Rabe Abubukar said in an exclusive interview with Xinhua the Joint Task Force (JTF) rescued the Ukrainian hostages overnight in battling the Movement for the Emancipation of the Niger Delta (MEND).
The JTF destroyed another key camp in the heart of Africa's biggest oil industry region, after storming Camp 5, the stronghold of MEND on Friday, according to the spokesman.
"On Sunday night, we rescue four Ukrainians in Delta State, they are in good condition as I speak with you and we never knew they were in that camp," he said.
"It was pertinent to state that Camp 5 has become history and all the equipment inside it has been reduced to rubbles and we are on the ground, we are controlling the place, it ceases to be camp 5 for good," Abubakar added.
The spokesman said the military will continue with their operations until the situation is stabilized, noting that they launched attacks on criminals who made those areas their abode.
MEND declared an "all-out war" on Friday amid advances of the JTF, which is getting the upper hand and vowing to crush it. More than 200 foreign workers have been kidnapped since the militant group was formed in January 2006.
MEND is suspected of hijacking the ocean-going vessel, the MV Spirit, on Wednesday and holding 22 crew members on board.
The JTF has also recovered the MV Spirit in its operations to free hostages.