South Korea says more trash balloons launched from North

South Korea on Tuesday announced North Korea sent another round of trash-filled balloons into the country. South Korea's president called the move "despicable" and "irrational," and vowed to uphold military readiness at the border.

South Korea said the North launched about 350 balloons carrying plastic bags of rubbish across the border on Monday, marking the North's fifth campaign since late May, The Associated Press reported. About 100 of the balloons eventually landed on South Korean soil, mostly in Seoul and surrounding areas, the news wire added.

South Korean President Yoon Suk Yeol called the North's balloon campaign "a despicable and irrational provocation" in a speech Tuesday marking the anniversary of the Korean War's outbreak, The AP reported.

South Korea's Yonhap News Agency reported the North sent more balloons Tuesday, citing the Joint Chiefs of Staff, who advised the public to not touch the balloons, and to report them to authorities.

Trash balloons in previous launches have not carried dangerous substances, but have included cigarette butts, wastepaper, vinyl and plastic bags. South Korea briefly turned on its loudspeakers along the border in response on June 9, and resumed anti-North Korean propaganda broadcasts.

The loudspeaker blasts stopped in 2018 after a rare meeting with North Korean leader Kim Jong Un, Reuters reported.

The balloon launches are an apparent response to a campaign organized by South Korean activists and North Korean defectors who have launched balloons with anti-North Korea leaflets and other items, The AP reported.

Joint Chiefs of Staff spokesperson Lee Sung Joon told reporters Tuesday the South Korean military is prepared to turn on its border loudspeakers again in response, The AP added.

Tensions between North and South Korea have persisted in recent months, and escalated last week after North Korean leader Kim Jong Un and Russian President Vladimir Putin signed an official partnership during Putin's state visit.

In the treaty, the leaders vowed to increase trade and defend each other in the event of an attack. The agreement marks a blow to the U.S., which has tried to isolate both nations for security purposes.

Yoon on Tuesday slammed the treaty, describing it as  “anachronistic," per The AP.

Last week, reports circulated that North Korea began building an apparent wall along the North Korean border, according to a BBC Verify analysis. 

An area of land inside of the Demilitarized Zone (DMZ), which serves as a 155-mile-long buffer zone between the two nations, also appeared to be cleared, per BBC.

The Associated Press reported last week North Korea’s construction could be seeking to make it harder for North Korean civilians to move to the south.

The Associated Press contributed reporting.