BAUCHI, Nigeria — A shadow Islamic extremist group has claimed responsibility for the kidnapping of seven foreign workers in northern Nigeria.

In a statement Monday, the group that calls itself Ansaru claimed the kidnapping of the one British citizen, one Greek, one Italian, three Lebanese and one Filipino on Saturday night.

Ansaru also threatened that Nigerian and European authorities shouldn't "act contrary to our conditions." The short statement offered no conditions, suggesting ransom demands would follow.