SEOUL, Korea, Republic Of -- Russia wants an investigation into South Korea's allegation that a Russian military plane violated South Korean airspace, a senior lawmaker said Wednesday, citing Moscow's acting ambassador. The U.S. called for close consultation between Washington and Seoul to deal with similar incidents in the future.

Seoul said South Korean fighter jets fired flares and 360 rounds of warning shots to drive away the Russian reconnaissance plane that entered its airspace twice Tuesday during a joint patrol with other Russian and Chinese bombers. Russia and China said none of their planes entered South Korean territory.

South Korea's Defence Ministry said it will hold talks with officials from the Russian Embassy on Thursday and that it has evidence that can prove Russia's territorial trespassing. Senior South Korean presidential official Yoon Do-han later said the evidence includes radar images and photos of the flare firing.

South Korea says the incident marked the first airspace violation by a foreign military plane since the end of the 1950-53 Korean War. Seoul officials said the five Russian and Chinese planes, including the Russian reconnaissance aircraft, made a highly unusual joint entrance to South Korea's air defence identification zone earlier Tuesday, prompting South Korean fighter jets to scramble.

Such a zone is not a country's territorial sky and extends beyond it. It is meant to give authorities an early warning of a possible incursion.

Some experts in South Korea say Russia and China may have wanted to see how decades-long trilateral security co-operation among South Korea, Japan and the United States would work amid escalating trade disputes between Seoul and Tokyo. The experts say China, embroiled in a separate trade war with the U.S., may have also attempted to display its military co-operation with Russia.

China's Defence Ministry said Wednesday that China and Russia carried out their first joint air patrol in Northeast Asia that "does not target any third party." Spokesman Wu Qian said in Beijing the two countries each sent two bombers for the patrols along established air routes and that they "didn't enter the territorial airspace of other countries."

In a message to South Korea on Wednesday, Russia repeated its position that none of its planes violated South Korean territory and that South Korean fighter jets threatened its planes with "unprofessional manoeuvrs," according to Seoul's Defence Ministry.

Earlier Wednesday, Yoon, the presidential official, said Russia's deputy military attache in South Korea, Nikolai Marchenko, told Seoul on Tuesday that a technical malfunction may have caused the incident. The comments triggered media questions about whether Russia admitted to the airspace violation. But after receiving Russia's new message later in the day, Yoon said he thinks Russia's position has changed.

The Russian Embassy in Seoul wasn't available to comment.

Also Wednesday, Russia's acting ambassador to South Korea, Maxim Volkov, told Yoon Sang-hyun, chairman of the South Korean parliament's Foreign Affairs Committee, that Russia feels "regrettable" over the incident, according to Yoon.

Yoon cited Volkov as saying Russia thinks an investigation was necessary and has requested related South Korean information.

Volkov told reporters he had explained to Yoon Russia's position on the incident but declined to provide the contents of their conversation.

Also Wednesday, South Korea's presidential national security director, Chung Eui-yong, discussed the issue with visiting U.S. National Security Adviser John Bolton. Chung told Bolton about South Korea's "resolute" response to the Russian airspace violation, and Bolton proposed that the allies closely co-ordinate over similar future incidents, South Korea's presidential office said in a statement.

Russia says two of its bombers were on a routine flight over neutral waters. Russia's Defence Ministry also denied Tuesday that South Korean jets fired warning shots.

The South Korean foreign and defence ministries on Tuesday summoned Volkov and Marchenko to register their complaints. They also summoned China's ambassador and the defence attache to protest Beijing's overflight.

The airspace that South Korea says the Russian reconnaissance plane entered is above a group of islets controlled by South Korea but also claimed by Japan.

Japan subsequently protested both Russian and South Korean actions, according to Chief Cabinet Secretary Yoshihide Suga. He said in Tokyo that the latest incident doesn't affect Japan's position that Seoul must first take steps toward resolving separate trade disputes between the two countries.

South Korea's Defence Ministry refuted the Japanese statement, saying Wednesday that Seoul will sternly deal with any foreign intrusion on the islets.

In a separate statement, the ministry said Defence Minister Jeong Kyeong-doo and Bolton agreed to co-operate to strengthen a trilateral security co-operation involving Japan and a bilateral co-operation between Seoul and Tokyo.


Associated Press writer Mari Yamaguchi in Tokyo contributed to this report