LONDON and SEOUL — Waste transported by a North Korean ‘garbage balloon’ landed at the South Korean presidential complex in the capital Seoul on Thursday, amid rising tensions between the two neighboring countries.

South Korea’s Presidential Security Agency “identified waste that exploded in the air and fell on the office grounds early this morning,” the agency said in a statement Thursday.

“Following a safety inspection, the agency collected the dropped items after confirming that they do not pose a hazard or contagiousness,” the agency added. “The agency is monitoring the situation in coordination with the Joint Chiefs of Staff.”

This is the second time a North Korean garbage balloon has fallen into the South Korean presidential office building.

Cross-border balloons have been an element of the recent deterioration in inter-Korean relations, with the period of diplomatic thaw from 2017 giving way to new tensions since the election of conservative South Korean President Yoon Suk-yeol in spring 2022 .

According to the South Korean military, the balloons were found with household waste, including paper, vinyl and plastic bottles. Some garbage balloons carried manure.

Several fires have also been reported in metropolitan areas attributed to “heat timers” attached to the balloons.

North Korea launched a total of 5,500 garbage balloons at South Korea 22 times from May 28 to September 23 this year, Lee Sung-joon, a spokesman for South Korea’s Joint Chiefs of Staff, said last month.

Seoul estimated that North Korea spent 550 million won (about $411,600) on producing the balloons, South Korea’s Yonhap news agency reported.

Lee said in September, after 120 balloons were launched, that Seoul would consider military action to shoot them down if necessary. “If North Korea’s continued waste balloons are judged to pose a serious threat to the safety of our citizens or have crossed the line, the military will take strict military action,” he said.

South Korean civilian groups have also launched balloons over the border, much to Pyongyang’s chagrin.

Such balloons often carry rice, essential medicines and leaflets critical of leader Kim Jong Un’s regime. North Korea has repeatedly protested such actions and threatened a response.

The border area was particularly tense this month. On October 15, Seoul said North Korea blew up two border roads and deployed “heavy equipment” for “further operations.”

South Korean troops along the border fired warning shots in response, South Korea’s Joint Chiefs of Staff said in a statement.

The blasts followed a North Korean warning that it planned to permanently close border access routes, cut rail and road links and strengthen defenses.

The explosions came shortly after Kim ordered his artillery forces – traditionally the most powerful threat to the capital Seoul, which is about 56 kilometers (35 miles) from the border – to be on full alert after accusing Seoul of flying drones over Pyongyang.

The confrontation on the Korean Peninsula could now spread to Ukraine, where Seoul, Kiev and Washington DC have accused Pyongyang of deploying troops in support of the Russian invasion.

Yonhap reported that Seoul is now considering sending weapons to Ukraine in response, after providing only humanitarian aid so far.

Yonhap also said South Korea is considering sending military and intelligence personnel to Ukraine to investigate North Korean battlefield performance and assist in the interrogations of captured North Korean fighters.

ABC News’ Ellie Kaufman contributed to this report.