Balloons carrying trash flying above the Seoul district of Jongno after being launched by North Korea, Oct. 8. Yonhap

South Korea's military said Friday North Korea has sent around 40 balloons filled with trash across the border into the South since the previous night, with most of them landing in the broader capital area.

The Joint Chiefs of Staff said it discovered about 30 of the balloons launched by the North from Thursday night to early Friday morning in the capital area, including Gyeonggi Province, which surrounds Seoul.

"Content found (from the balloons) included propaganda leaflets against South Korea and nothing that posed safety threats," the military said.

Since late May, North Korea has floated such balloons into the South on 32 occasions, including the latest, in retaliation against anti-Pyongyang propaganda leaflets sent across the border by activists in the South. (Yonhap)