Police yesterday were seeking the four Kalashnikov-wielding assailants who burst into the Ethniki Amyna metro station, in northeastern Athens, and forced cashiers at the ticket-issuing office to hand over more than 250,000 euros in the first robbery of its kind in the capital. The robbers entered the station just before 2 p.m., when the entrance hall was full of commuters emerging from the underground platforms or waiting to buy tickets. According to police, the incident did not spark a panic nor cause any injuries, as the robbers blended into the crowd of commuters and did not use their guns. Officers said the assailants had probably planned the heist after a long period of observation. Before threatening the cashiers, the assailants reportedly forced a security guard to hand over his gun and handcuffs. Bagging the cash, they exited the station, boarded two motorcycles and fled, witnesses said. There was no sign of them by late yesterday.