North Korea claimed Friday that South Korean drones infiltrated its airspace over Pyongyang on three occasions this month to drop leaflets criticizing its leader Kim Jong-un.

The North showed what it said were photos of a drone scattering leaflets over Pyongyang at night as well as photos of those purported leaflets. Kim Yo-jong, the younger sister of the North's leader Kim Jong-un, said that a horrible catastrophe would happen without fail at the moment of a South Korean drone being spotted again.

It is not clear yet who sent the drones. No civic group has claimed responsibility. The official position of the South Korean military is that it cannot confirm if the North Korean claims are true.

About two years ago, North Korean drones infiltrated airspace over Seoul, Incheon and Gyeonggi Province for five hours and went back. One of them violated the no-fly zone over Yongsan where the presidential office is located. In 2017, a drone that took off near Geumgangsan in North Korea crashed in Inje, Gangwon Province, and there were about 550 photos of South Korean military bases found to be contained therein. In 2014, three crashed drones were found in Gyeonggi and Gangwon provinces. Their coordinates programmed for both departure and return were in North Korea.

It is ironic and unreasonable that the North is threatening to attack South Korea for doing something they have done repeatedly themselves. Furthermore, their claims are unconvincing. All the North has to do is apologize and stop flying trash-filled balloons southward.

If the North wants to prove that the drones in the photos were flown by the South Korean military, it should present evidence.

The photos the North presented show a drone-like flying object dropping leaflets in the sky. But it has not disclosed a photo of its identifiable fuselage.

Also, the leaflets are said to differ from those sent by South Korean civic groups in light of the phrasing and page design. They mention the dire economic conditions of North Korea and show Kim Jong-un and his daughter wearing an expensive watch and a luxury-brand coat, respectively.

The North is likely to use the drone infiltration as a pretext to tighten control over its residents and launch armed provocations against the South. Pyongyang disclosed this issue to residents through its propaganda media apparently to incite hostility toward the South. It is rare for the North Korean media to domestically show leaflets criticizing Kim.

Without convincing evidence, North Korea stated categorically that the South Korean military drones infiltrated its airspace and it is escalating threats to the South. Pyongyang said it has put fully armed artillery units near the border with the South on standby to shoot down South Korean drones if they cross the border again and to prepare for a situation where armed clashes may expand afterward. The South Korean military warned that the Pyongyang regime will be doomed on the very day when it harms the safety of people. The military authorities must recheck defense readiness for an immediate and overwhelming response to any North Korean provocation.

The main opposition Democratic Party of Korea criticized the government's position, saying it is irresponsible to avoid confirming whether the North Korean claims are true.

Rep. Park Jie-won of the party, who headed the National Intelligence Service under President Moon Jae-in, went a step further. He said that South Korea made the first provocations by letting civic groups send leaflets to the North and installing loudspeakers near the border to deliver anti-North Korean messages. But the North does provocations all the time, picking on the South.

Park argued that saying Seoul cannot confirm if North Korean claims are true practically means admitting to sending the drones. This is in the same vein as Kim Yo-jong’s remark that the South Korean position amounts to owning up to being the main culprit or an accomplice to the drone infiltration.

When it comes to security, the nation should be united. It is not desirable to criticize the military while refraining from criticizing the North Korean threat, even if an opposition lawmaker offers such criticism. That plays into the hands of North Korea seeking to incite division and conflicts in the South.