In a highly unusual incident, a Russian warplane reportedly violated South Korea airspace three times on Tuesday morning, prompting Seoul to scramble fighter jets to intercept it, drop flares and even fire warning shots, according to South Korean media.

However, Moscow disputes the South Korean version of events.

The Russian aircraft allegedly entered South Korea’s Air Defense Identification Zone (KADIZ) off the peninsula’s east coast, then flew further into South Korean airspace, according to a report on Yonhap, South Korea’s part-government owned newswire, that cited Seoul’s Joint Chiefs of Staff.

South Korea scrambled F15 and F16 jet fighters to head off the aircraft. The Russian aircraft then left both the airspace and the KADIZ, before intruding twice more. The three intrusions took place between 09:09 and 09:56, according to Yonhap.

According to television reports in Seoul, the South Korean aircraft fired 360 bullets approximately one kilometer ahead of the Russian aircraft as a warning.

There was confusion about the kind of Russian aircraft involved. Yonhap used the term “bomber,” but a message sent to foreign reporters by the Presidential Blue House said it was an early warning plane.

The Blue House message also stated that South Korea’s National Security Advisor had communicated Seoul’s displeasure with the intrusion and asked his counterpart, the head of the Russian Federal Security Service, to examine what was behind the incident.

Earlier in the day, four Russian and Chinese aircraft had entered the southern KADIZ, Yonhap reported. However, these aircraft, which were apparently operating in concert, did not enter South Korean air space.

Russia’s response

Moscow, in a statement subsequently released by its Ministry of Defense, offered a very different narrative.

According to a statement from the Russian Ministry of Defense quoted by AFP, South Korea jets unsuccessfully attempted to interfere with a Russian air exercise by not one, but two TU-95 strategic bombers “over the neutral waters of the Sea of Japan.”

The Russian statement accused two South Korean aircraft of carrying out “unprofessional maneuvers” by crossing their flight path and by “threatening their safety.”

However, Moscow said there had been no attempt at communication, nor had any warning shots been fired. “Had the Russian pilots felt under threat the response would not have been long in coming,” the Russian defense ministry statement said.

It is possible that, if the South Korean guns were not heavily loaded with tracers rounds, the warning shots would not have been spotted.

While South Korean reports said Tuesday’s incident was the first violation of its airspace by a Russian aircraft, Russian pilots have ample experience playing games of aerial chicken with Western air forces in NATO’s area of operations.

Unanswered questions

Much about the incident remains unclear.

KADIZ, like other ADIZs established by other states, is a unilaterally drawn series of lines on a map that is not officially recognized by any international treaty. In the region, China’s ADIZ overlaps with those of both Japan and South Korea. In an ADIZ, incoming foreign aircraft are supposed to identify themselves, though this rule is not universally followed.

Airspace is a different matter. Under international law, South Korean airspace would be airspace above South Korean land and above its territorial waters, which extend 12 miles off its coast.

Complicating the issue is that the Yonhap report stated that the first intrusion took place near or over the twin islets known as Dokdo in Korean. Set approximately equidistant between Japan and South Korea in the middle of the Sea of Japan – which South Korea calls the East Sea – the islets are administered by Seoul and garrisoned by South Korean police.

However, Dokdo’s ownership is diplomatically disputed by Japan, which calls the islets Takeshima. On many maps and data sources, including Wikipedia, the islets are known as Liancourt.

Given this, it is unclear whether the skies above the islets are sovereign airspace under related international laws. For example, Philippine President Rodrigo Duterte last year warned China not to claim airspace above disputed islands in the South China Sea.

However, Seoul’s position is clear. Officially, it does not recognize Japan’s demand, and so does not consider the ownership of the islets disputed, a South Korean government official clarified to Asia Times. Moreover, it considers the skies over the islets sovereign airspace, the official said.

Meanwhile, while the ownership of the islets near or over which the aerial incident occurred is hotly, although not kinetically, contested between Seoul and Tokyo, Moscow – even though it maintains a naval base at Vladivostok, in the north of the Sea of Japan – has no apparent claims to them.

The Russian statement said its aircraft were 15 miles, or 25 kms, from the sensitive islets.

Moreover, it is more usual for Chinese aircraft to buzz Japanese and South Korean ADIZs. In the first half of last year, Japanese aircraft scrambled 561 times to respond to Chinese incursions into its ADIZ. South Korea – whose ADIZ overlaps with China’s ADIZ south of the Yellow Sea – saw more than 100 incursions in the same period.

It is not known if the reported Russian and Russo-Chinese incursions on Tuesday represent a new, concerted stance in Northeast Asia.

Hawkish US National Security Advisor John Bolton was expected to arrive in Seoul later on Tuesday, following a visit to Japan. While Bolton’s mission is designed to firm up security cooperation among America’s Northeast Asia allies, Seoul and Tokyo are teetering on the brink of a trade war that has raised emotions in South Korea to fever pitch.