The Foreign Ministry has begun studying whether the April 12 cyber attack by North Korea violated the international law as part of efforts to ward off additional attacks, an official said Wednesday.

“The exercise of their right in a way that inflicts damage on other countries is illegal under the international law,” the official said on condition of anonymity.

Prosecutors on Tuesday concluded that the communist state masterminded the “unprecedented cyber terror” that paralyzed the banking system of the National Agricultural Cooperative Federation for several weeks. They said that the methods used in last month’s attack were similar to those used in the two previous attacks in July 2009 and March last year.

The ministry considers seeking international response to such cyber attacks as North Korea is expected to continue such attacks, local news reports said.

Last March, the ministry asked for cooperation from the International Civil Aviation Organization in stopping North Korea from jamming communications signals in South Korea.

Meanwhile, the Unification Ministry issued a rare statement, urging the North to immediately halt its cyber attacks against South Korea.

“We urge North Korea to immediately stop its indiscriminate acts of cyber terrorism including the hacking of civilian financial institutions in the South,” said the ministry’s vice spokesperson Lee Jong-joo.

“In close cooperation with related government agencies, we will continue to take measures needed to bolster our capabilities to respond to cyber terror.”

Lee said the government has no plan yet to send a letter to the North to protest the recent attack on Nonghyup. However, she said that the government will study what additional measures should be taken to deal with the recent case.

After the prosecution announced Tuesday that the North was behind the cyber attack, the ministry issued a commentary, saying that “the attack was a provocation against the South Korean society and the North deserves condemnation for it.”

By Song Sang-ho (sshluck@heraldcorp.com)