A gunman who held 18 bank employees and customers hostage following a botched robbery in Piraeus yesterday afternoon surrendered and freed his captives unharmed following hours of negotiations with police. The man, a Greek national, stayed inside the branch of National Bank after his two accomplices, who had been standing guard outside, spotted police and fled. The two lookouts, ethnic Greeks from the former Soviet Union and Egypt, were arrested almost immediately. But the would-be robber refused to emerge from the bank and took hostage the 18 people within. Armed with a pistol and two hand grenades, he fired warning shots inside the bank, located on busy Iroon Polytechneiou Street, and demanded a getaway car. He tried to escape, using four hostages as human shields, but retreated on seeing the large police presence outside. After several hours of talks with police negotiators, the man freed his hostages and gave himself up.