Takeoffs and landings at South Korea’s Incheon international airport have been disrupted for about three hours because of balloons launched by North Korea filled with refuse, an airport spokesperson said, Azernews reports citing the Guardian.

One balloon landed on the tarmac near passenger terminal two and the three runways at Incheon were temporarily shut down on Wednesday, the spokesperson said.

North Korea has flown balloons carrying rubbish into South Korea since late May, with hundreds landing in South Korea.

Several balloons were spotted in and around the airport boundaries, the spokesperson said, adding that this was not the first time operations at the airport – which is about 40km from the North Korean border – had been disrupted by balloons nearby.

The disruption to domestic and international flights occurred between 1.46am and 4.44am on Wednesday, and the runways have reopened since then, Incheon International Airport Corporation said.

Flight volume at that time of day is usually low. FlightRadar24 showed eight arriving cargo and passenger flights were diverted to South Korea’s Cheongju or Jeju airports during that time, and one China Cargo freighter from Shanghai was diverted to Yantai, China.

Several more landings were delayed, and departures were delayed by several hours.

North Korea has said the balloons are retaliation for a propaganda campaign by North Korean defectors and activists in the South who regularly send over balloons carrying food, medicine, money and leaflets criticising the North’s leaders.

Among the items carried by the North Korean balloons have been articles printed with Hello Kitty characters, badly worn clothing, and soil containing traces of human faeces and parasites, South Korea has said.

South Korea’s military on Wednesday said about 100 balloons had fallen to the ground between Tuesday and Wednesday, mostly in the capital, Seoul, and the surrounding Gyeonggi province. Most carried just scraps of paper.