Seoul city gov’t issued text alerts advising people to stay indoors and be cautious of objects falling from the sky.

South Korea says it has detected balloons likely carrying trash launched by North Korea, in the latest round of a months-long campaign that Pyongyang says is retaliation against against South Korean civilian activists flying propaganda leaflets across the border.

South Korea’s Joint Chiefs of Staff (JCS) said in a statement on Wednesday that an unspecified number of balloons could reach the northern Gyeonggi Province, north of the capital, Seoul.

The JCS advised citizens that if they see a fallen balloon, they should report it to the police or military and not touch it.

The Seoul city government issued text alerts that the balloons had been spotted and advised people to stay indoors and be cautious of objects falling from the sky. There have so far been no reports of injuries or damage.

Since late May, North Korea has launched thousands of trash balloons in what it says is a response to anti-Pyongyang leaflets sent by North Korean defectors and activists in South Korea.

The last time Pyongyang launched trash-filled balloons was on August 10.

North Korea is sensitive to the leaflets from activists about life outside of the country due to fears that the information could pose a threat to the country’s leader, Kim Jong Un.

Previous North Korean balloons have dropped wastepaper, cloth scraps and cigarette ends.

In July, one trash-filled balloon fell on the South Korean presidential compound, raising concerns about the vulnerability of critical South Korean facilities.

In response to the balloons, South Korea’s military has begun blasting anti-Pyongyang propaganda broadcasts and K-pop songs near the border.

The latest round of balloon launches come after the leaders of South Korea and New Zealand slammed North Korea’s weapons programme earlier on Wednesday.

South Korea’s President Yoon Suk-yeol and New Zealand’s Prime Minister Christopher Luxon condemned Pyongyang’s pursuit of nuclear weapons and ballistic missiles as well as its growing military cooperation with Russia amid its war in Ukraine.

The balloons also come as South Korea undertakes military exercises with the United States and looks westwards.