LAGOS , Nigeria ( CNN ) -- Nigeria 's military has rescued 18 hostages held by militants in its oil-rich Niger Delta region , a military spokesman said Monday . File image shows Movement for the Emancipation of the Niger Delta fighters . The first group -- nine Filipinos and five Nigerians -- were released on Saturday , while four Ukrainians were released on Sunday , according to Col. Rabe Abubakar , spokesman for the Nigerian military 's joint task force . Nigeria 's military began clearing the western Niger Delta region last week , its first major operation against the Movement for the Emancipation of the Niger Delta , an armed militant group that demands a better distribution of the country 's oil wealth . Both the Nigerian military and the militants have said the ongoing fighting has resulted in a high number of casualties . As many as 1,000 have been killed , according to Victor Burubo , a spokesman for the Ijaw National Council which represents the region 's largest ethnic group . However , aid groups and journalists have been unable to verify that figure . `` We want the international community to know that we are getting rid of criminals and terrorists in our communities so foreigners who come here to work and invest are safe , '' Abubakar said . Four villages near the militants ' camps have been destroyed in the fighting , Burubo said . However , the military spokesman stressed that Nigerian forces are not targeting civilians , blaming such attacks on the militants . `` We are not attacking villages -- just ( militant ) camps , '' Abubakar said . On Friday , MEND declared `` an all-out war '' on the government after what it said was a deadly bombing raid on civilians . It is not the first declaration of war by MEND , which demands that more of Nigeria 's oil wealth be reinvested in the region instead of enriching those the militants consider corrupt politicians . The militant group declared war against the government in September for what it said were unprovoked attacks . At that time , MEND destroyed several oil facilities , forcing Nigeria to cut its oil exports by as many as 1 million barrels of oil per day , or 40 percent . The recent violence -- which has included attacks on pipelines and hostage-taking -- has limited shipment of crude oil supplies out of Nigeria , Africa 's largest producer . MEND has threatened to blockade oil vessels , and has warned oil companies in the region to leave and `` cease oil production until further notice . '' The militant group said Friday the country 's armed forces conducted `` indiscriminate aerial bombardment on the defenseless civilians in the Gbaramatu area of Delta state . '' It said the strikes were punishment `` for the humiliating defeat '' of the army in raids on two militant camps Wednesday . `` Casualties are mostly women , children and the elderly who could not get away quickly into the bush or high sea , '' the militant group said . The military says it is responding to the militants ' attacks on troops , hijackings of vessels , and threats to innocents , such as the `` expatriates who were given ultimatum to leave the region by the militants . '' It characterized the various claims by the militants as `` propaganda . '' `` We are not at war with any individuals or groups in the region , '' Abubakar said . `` Ours is to protect lives and property and also to rid the region of criminals who hide under the guise of struggle agenda to perpetrate crime . '' CNN 's Christian Purefoy contributed to this report .
9 Filipinos and 5 Nigerians released Saturday , 4 Ukrainians released Sunday . Nigeria 's military started clearing the western Niger Delta region last week . Fighting against militants demanding better distribution of Nigeria 's oil wealth . Movement for the Emancipation of the Niger Delta has declared ` ` all - out war ''