Nigerian police are denying reports that they are using increasingly violent means, including torture and illegal killings in their fight against militants in the volatile Niger Delta region. Amnesty International reported Thursday it has seen an upsurge of disappearances and violence in the oil-rich region. 

But a Nigeria national police spokesman, Emmanuel Ojukwu said torture and illegal killings are not official Nigerian government policies. 

Aster van Kregten, Amnesty International  researcher on Nigeria told VOA her organization wants to know the whereabouts of four unarmed men and a former gang member in the Niger Delta.

"We recently received reports about the case of Mr. Chika Ibeku who was arrested last week by the Nigerian police in Port Harcourt, Rivers State. His family visited him and saw him while he was in police detention, and then after?he was transferred to another police station. From that point, the police have denied that he was in their detention. This is extremely concerning. We don't know about his whereabouts and we don't know what happened to him. We do know that along with him there were three other men, and we don't know what happened to them," she said.

Nigeria national police spokesman Emmanuel Ojukwu told VOA that torture and illegal killings are not official Nigerian government policies. He said the Niger Delta militants have not only been at war with themselves but unleashed violence against the police.

"The last part talked about torture and illegal killings. Those are not the hallmarks of Nigerian police. We do not normally tolerate nor compromise such. But talking about violence in Niger Delta, there has been a lot of unrest in the Niger Delta region of Nigeria. The Nigerian police and the security forces have been contending with that development. But one thing is that there are many cult groups, rival gangs who are at war between themselves and among themselves. So they are the ones that unleash violence not only on themselves but also on the security forces, including Nigerian police," he said.

Ojukwu said a few months back Niger Delta militants killed about 17 police officers, burnt down a police station and destroyed government property.

"That is violence on the part of militants, and of course nobody will expect the Nigerian police to full its arms and allow the militants to overrun the place, otherwise Nigeria will become ungovernable. The Nigerian police are rising to the situation in accordance with laws of Nigeria," he said.

Van Kregten said Amnesty knew that Chika Ibeku was supposed to be a member of one of the criminal gangs in the Niger Delta and reportedly he had gone to the police station to hand over his guns in line with the government's recent offer of amnesty for militants in the Niger Delta.

Van Kregten said the Nigerian government has a duty to abide by its own constitution and international obligations.

"I would like to reiterate that under the Nigerian constitution and also under Nigerian international obligations, all suspects of any crime should be brought before a court within reasonable time, and reasonable time is 48 hours. And we know that Mr. Chika Ibeku was arrested in the seventh of April 2009 and until now he has not been brought before a court. So we really want to know did the Nigerian police arrest him, is he in their detention and what happened to him?" she said.

Van Kregten said Amnesty wrote to the police commissioner of Rivers State this month about the whereabouts of Ibeku, but she said the police did not respond to Amnesty's inquiry.

"We really want to know what happened to Mr. Ibeku. I think it's extremely important that the Nigerian police is clear about what they do. If they arrest people then they should bring them to the court, and the Nigerian constitution is very clear on that. They should suspects to the court within 48 hours. We really want to know what happened to Mr. Ibeku, and we really want to see him in court," Van Kregten said.

Police spokesman Ojukwu said he did not know about the detention of Ibeku and others whom Amnesty claimed have not been heard from.

"I do not know about the gang members or their leaders if they are held in detention. Normally most of them who are held in detention are out of speculation. But they do have contacts with their love ones in accordance with the law. So I am not aware that they have not been heard from for quite some time," Ojukwu said.