North Korean computer hackers have been blamed by prosecutors for an attack that paralysed a South Korean bank.
The system crash affected millions of customers
The crash of Nonghyup's (NH) computer system last month prevented millions of customers from using the bank's credit cards and ATMs for several days.
The intrusion is the latest in a series of cyber attacks thought to have originated from the secretive state.
Prosecutors in the South's capital Seoul said it was a new form of cyber terrorism, "meticulously prepared and executed" by the same group that hacked into South Korean government and business websites in 2009 and March this year.
It is not the first time North Korea has been accused of hacking
The South's unification ministry has urged Pyongyang to halt the attacks.
South Korean media have previously accused North Korea's government of being behind "internet warfare".
The countries are still technically at war, having only signed a truce to end the Korean War in 1953.