PORT-AU-PRINCE – Rights groups demanded Haiti arrest former dictator Jean-Claude Duvalier yesterday for crimes against humanity after his surprise return from 25 years in exile, which strained an edgy political atmosphere in the volatile Caribbean state.

Analysts said the unexpected arrival in Port-au-Prince on Sunday of “Baby Doc” Duvalier, who had fled his homeland in 1986 to escape a popular revolt, could only complicate the climate of nervous uncertainty. Tensions are running high following chaotic and inconclusive elections.