ATHENS — As the Greek government struggles to save its debt-racked economy from collapse, another crisis is growing in the capital: A sharp increase in violent crime is stirring unrest among a public already demoralized by unending economic hardship.

Once a rarity in Athens, long proclaimed one of the safest European capitals, crime has grown uglier. Knifings are no longer unusual and assault rifles have been used in armed raids on street kiosks and jewelry shops.

According to police statistics for 2010, the most recent available, street robberies in the capital doubled compared with 2009, robberies of taxi drivers nearly quadrupled and homicides were up 50 percent. The figures are stark compared with those in other Greek cities where increases are mostly in the single digits.

“Crime has not just increased — it has become more complex and more violent, particularly organized crime,” said Thanassis Kokkalakis, a police spokesman.