Soldiers in hazmat suits check debris from a trash-laden balloon launched by North Korea that fell on a street in Jeong-dong, central Seoul, Wednesday. Yonhap

Several trash-carrying balloons from North Korea landed on the presidential office compound in Yongsan District, Seoul, Wednesday, sparking concerns about potential security lapses in South Korea's defense against unconventional provocations from Pyongyang.

This is the first time the trash-laden balloons have landed on the presidential compound, out of over 2,000 balloons Pyongyang sent on 10 occasions since late May.

The persistent balloon launches are proving to be a major headache for the South Korean military, which appears to lack an effective strategy to deter them other than repeatedly collecting the debris from the ground.

In a text message sent to reporters at around 7:25 a.m., the Joint Chiefs of Staff (JCS) said the balloons launched by North Korea appeared to be heading toward northern Gyeonggi Province, and urged residents to be wary of falling objects.

The military detected around 300 balloons in the air, with approximately 250 falling within South Korea's territory, mostly in Seoul and the surrounding Gyeonggi Province.

The Presidential Security Service (PSS) said some balloons landed on the presidential compound, but did not specify the exact number.

"Following an investigation by the chemical, biological, radiological, and nuclear response team, it was confirmed that the objects posed no risk or contamination and were subsequently collected," the PSS said.

The presidential office said it had been monitoring the balloons' precise location in real-time until they landed. It is unclear whether President Yoon Suk Yeol was in the office when the balloons landed, but his office said earlier that he had no official appointments on Wednesday.

Trash-laden balloons in the skies over North Korean are seen from in Paju, Gyeonggi Province, South Korea, Wednesday. Yonhap

"We were observing in real-time through surveillance equipment. We accurately identified the location and safely handled it after it landed," a senior presidential official told reporters on condition of anonymity.

A military official told The Korea Times that there is a low possibility North Korea deliberately targeted the presidential office with the balloons, as their courses and landing locations are largely affected by wind and weather conditions.

The official added that the government's protocol regarding the North's trash balloons — retrieving them after they fall instead of shooting them down — remains unchanged, saying, "Since we don't know what substances the balloons might contain, it is difficult to deal with them while they are airborne."

At least one balloon also landed on a United States Forces Korea (USFK) base in Yongsan District, Seoul, on the same day, according to several media reports. The USFK was not immediately available for comment.

The latest wave of balloons, which marks the 10th such offensive since the first one on May 28, occurred three days after South Korea's military expanded its anti-North Korean propaganda loudspeaker broadcasts along the inter-Korean border to full-scale starting Sunday afternoon.

This move was in response to Pyongyang's repeated balloon launches despite multiple warnings.

The broadcasts, which include K-pop songs and news critical of the North Korean regime, are part of South Korea's psychological warfare tactics aimed at demoralizing the North's frontline troops and residents.

The military is believed to have 24 fixed loudspeakers, which are audible at distances of up to 24 kilometers at night, and 16 portable speakers with a greater range, deployed in front-line areas.

"The speakers are currently in operation from 6 a.m. to 10 p.m. every day since Sunday," a military official said. The official declined to comment on the exact number of loudspeakers currently in operation, citing security reasons.

Hong Min, a senior researcher at the Korea Institute for National Unification, a state-run think tank, commented that the South Korean military seems to be struggling to devise an effective countermeasure beyond the propaganda speakers.

"It's not easy for the military to come up with a clear tit-for-tat response. If the trash balloons are considered highly threatening, the response would logically be to shoot them down. However, at this point, it's difficult to view them as a serious military threat, and intercepting the balloons midair could pose bigger risks to the public," Hong said.

There have been no reports of hazardous materials in the balloons so far, according to the military, which have primarily contained wastepaper, although earlier ones even included excrement.

Debris from a trash balloon floated into the South by North Korea is scattered on a street in Jung District, Seoul, Wednesday. Yonhap

Some conservative lawmakers here have argued that the military should take a more hardline approach by striking the origin of the balloons, but critics worry this could escalate military tensions.

The North Korean regime argues that the trash balloons are a tit-for-tat response to South Korea-based civic activists releasing anti-Pyongyang leaflets and USB drives containing K-pop and trot music into North Korea.

These civic groups, mostly comprised of North Korean defectors, remain resolute about their campaign to inform North Korean residents of the outside world.

Park Jung-oh, a defector-turned-activist, said he floated hundreds of plastic bottles packed with rice, USB drives, and Tylenol into the West Sea near Ganghwa County in Incheon on Monday. The USB drives were loaded with content from the Bible, Korean dramas and American action movies.

"We've been sending the bottles twice every month for the past few years, and we will continue to do so," Park said, Wednesday.