Prosecutors have said that Islamists arrested in Berlin and western Germany on Thursday may have been planning an attack on the capital. [...] There are conflicting reports in the media about what the exact target of the attack was, with tabloid Bild citing investigators who say it was Alexanderplatz, the iconic center of the former east of the capital. Berlin daily Tagesspiegel meanwhile, says popular tourist spot Checkpoint Charlie - once the most famous crossing in the Berlin Wall - was to be hit, citing security sources. [...] Security sources told DPA the group's ringleader was a 35-year-old Algerian arrested...