Japan said Tuesday it "strongly" suspects three Chinese spy balloons entered its airspace between 2019 and 2021.
Three "balloon-shaped flying objects" were detected between November 2019 and September 2021, the Japanese Ministry of Defence said, adding that these were "strongly presumed" to be "unmanned reconnaissance" aircraft flown by China.
The ministry said it had asked the Chinese government to "confirm the facts regarding this matter through diplomatic channels" and strongly requested that this not happen again.
Beijing on Wednesday rejected Tokyo's allegations.
"We firmly oppose the Japanese side's smear campaign against China in the absence of conclusive evidence," Chinese Foreign Ministry spokesperson Wang Wenbin said in a regular press briefing.
The Japanese allegations follow the flight of a Chinese high-altitude balloon over the continental United States earlier this month.
US officials have claimed that balloon, which was shot down by a US Air Force jet off the East Coast near the Carolinas, was part of a large Chinese military surveillance program that has conducted at least two dozen missions over at least five continents in recent years.
China, however, has claimed it was a civilian research vessel blown off course.
Wang, the Chinese Foreign Ministry spokesperson, accused Tokyo of falling in step with Washington with its new allegations.
Japan should "uphold an objective and impartial position" and "stop following the US" by engaging in "deliberate speculation," Wang said.
The Japanese Ministry of Defence warned in its statement that it would "strive to collect and monitor" any balloons that intruded into Japan's airspace without permission.
Asked if Japan Air Self-Defence Force jets would shoot down any unauthorized balloons, Defence Minister Yasukazu Hamada said this was possible.
"Necessary measures may be taken when deemed necessary to protect the lives and property of citizens," Hamada said.
