Russia has strongly denied ever apologising for violating South Korean airspace, as the fall-out from an incident involving warplanes from four countries continues.
South Korea’s presidential office earlier said a Russian official had expressed “deep regret” for Tuesday’s aerial intrusion in north-east Asia.
It says a Russian aircraft twice violated its territorial airspace during a joint exercise with China.
But Moscow denies any intrusion.
South Korean jets fired nearly 400 warning shots and 20 flares on Tuesday near the Russian surveillance plane that both it and Japan said flew near disputed islands that the two countries claim.
On Wednesday, South Korea’s government said that a Russian official had admitted the violation on Tuesday, saying it was unintended and that Moscow would immediately launch an investigation into the case, which the official blamed on a “technical glitch”.
“Moscow said if the aircraft flew according to an initially planned route, this incident would not have occurred,” a spokesman for the presidential Blue House, Yoon Do-han, told reporters.
Meanwhile, China has defended the exercise, which was the first ever joint air patrol between it and Russia.
Defence ministry spokesman Wu Qian told reporters they “strictly abided by the relevant regulations of international law and did not enter the airspace of other countries”.
Japan also scrambled bombers during Tuesday’s incident.