KARACHI: Pakistan arrested 27 Indian fishermen and impounded their four boats on Saturday for allegedly fishing in its territorial waters in the Arabian Sea, a Pakistani maritime security official said. Such arrests are frequently carried out by both countries, as the maritime border is poorly defined and many fishing boats lack the technology needed to be certain of their precise location. The fishermen often languish in jail even after serving their term, as poor diplomatic ties between the two arch-rivals mean fulfilling official requirements can take a long time. Muhammad Hassan Setho, a senior prison official, said there were 420 Indian fishermen in Karachi jail.