North Korea has sent trash-laden balloons over the South Korean border three times in two days.

The South Korean Joint Chiefs of Staff(JCS) said Thursday that the North began another balloon launch Thursday at about 7 p.m., adding the balloons might land in Seoul and northern Gyeonggi Province considering the direction of the wind. 

The JCS urges people to report any balloon sightings to a nearby military unit or police station.

Previously, North Korea launched trash balloons between Wednesday night and early Thursday, and again Thursday morning. 

The JCS said the North sent about 420 balloons between Wednesday night and early Thursday and 60 more for three hours starting Thursday at 9 a.m., with 30 of the balloons landing in Seoul and 70 in Gyeonggi Province. 

North Korea has been sending trash balloons since late May in response to anti-Pyongyang leaflet campaigns by defectors’ groups in South Korea.