Lagos, Nigeria ? A man who identified himself an American kidnapped by militants in Nigeria’s oil-rich southern delta last month said Tuesday he had been separated from two other hostages and feared for his life.

During a telephone call with The Associated Press, militants of the Movement for the Emancipation of Niger Delta passed the phone to the man, who identified himself as Cody Oswald.

Militants have been holding Oswald and two others – American Russell Spell and Briton John Hudspith – since a Feb. 18 raid on an oil industry barge. It was unclear why the hostages were split up.

He said he was separated from the other two on Saturday. “Since then I’ve not seen them, and I really fear for my life. Something needs to happen to see that their demands are met,” he added, before the phone was apparently taken from him.

The militants group claims to be fighting to win a greater share of oil wealth on behalf of the Niger Delta’s impoverished inhabitants, who have remained poor despite the fact that most of Nigeria’s oil is being pumped from the swampy region. The government calls the militants criminals and oil thieves.