North Korea has accused South Korea of flying drones over Pyongyang to drop anti-regime propaganda leaflets.

In a statement released on Friday, the North's foreign ministry claimed that Seoul flew drones into Pyongyang during nighttime on October 3, 9, and 10 for the propaganda activity. The North also released photos of the claimed drones and leaflets.

While describing the drone flights as a "dangerous provocation," North Korea said it's a "serious military attack" for which Seoul must pay a price.

Pyongyang also said its military has begun preparations to respond to a development in the situation, and is ready for "all means of attack." It also warned of an immediate response without warning if Seoul repeats the infiltration.

Following the announcement, North Korea flew trash balloons into the South for the 28th time this year.