South Korea has said it believes North Korea recently attempted to hack into its government computer systems following a nuclear test earlier in the month.
South Korea has been on heightened military alert since the nuclear launch on 6 January, although US officials doubt that the country has achieved such technological advancement.
"At this point, we suspect it is an act by North Korea," said Jeong Joon-hee, a spokesman of the South's Unification Ministry when asked about reports that the North might have attempted cyber-attacks.
He said that the authorities are currently investigating the matter but declined to give any further details.
South Korean President Park Geun-hye only last week said that attacks from its neighbour were expanding to include cyber warfare in addition to using drones to infiltrate the South.
North Korea has been using balloons to drop propaganda leaflets in the South, amid heightened tension on the Korean peninsula since the nuclear test.
Unconfirmed news reports have emerged in recent weeks that the computer systems of some South Korean government agencies and companies had been infected with malicious software.
It has been speculated that the software originates from the North.
Defectors from the North have also previously said the country's military spy agency operates a sophisticated cyber-warfare unit that attempts to hack and sabotage enemy targets.
The North has had a reputation for exaggerating its own successes in the past. Earlier this month, footage released by its official news agency displaying a ballistic missile launching from a submarine was shown to be doctored to cover the fact that the missile exploded in the water shortly after being fired.