According to the conditions of her parole, Berenson must remain in Peru until 2015. Yet when she was given permission to visit the US last month, many Peruvians expected her never to return.

Militants with the Boko Haram group reportedly attacked Damaturu with explosives and gunfire, and battled with Nigerian security forces who dislodged them from a hideout in the north of the city, an army official told reporters in Abuja, the capital.

The Nebi Akasha mosque was also defaced with racist graffiti, including "A good Arab is a dead Arab" and "Muhammad is a pig."

The gang members called themselves the "National Socialist Underground" after Adolf Hitler's National Socialist (Nazi) party.