Bundles of trash connected to a balloon sent by North Korea are seen in a rice paddy in Incheon, west of Seoul, in this file photo taken Jun. 10. (Yonhap)

North Korea sent more than 180 trash-carrying balloons toward South Korea overnight, the Joint Chiefs of Staff said Thursday, in what marked its third consecutive balloon launch this week.

Some 70 balloons, largely carrying small pieces of paper, mostly landed in Seoul and the northern part of Gyeonggi Province that surrounds the capital, the JCS said in a notice to reporters.

As of 9 a.m., there were no balloons floating in the air, while an analysis of retrieved trash has so far indicated they do not contain harmful substances, according to the JCS.

Since May 28, North Korea has launched thousands of balloons over seven instances in a tit-for-tat move against anti-Pyongyang leaflets sent by North Korean defectors and activists in the South.

The military has disposed of much of the retrieved trash while analyzing and storing samples, as well as any noteworthy items, a JCS official said.

In response to the balloon campaign, South Korea briefly blared anti-Pyongyang broadcasts through its border loudspeakers on June 9 for the first time in six years.

The JCS said it remains ready to turn on the loudspeakers at any time and warned the move would depend on the North's actions.

North Korea has bristled at the propaganda campaigns amid concern that an influx of outside information could pose a threat to its leader Kim Jong-un and the ruling regime. (Yonhap)