South Korea has been forced to repeatedly shut down runways at the two main airports for the capital Seoul since June due to disruption from balloons carrying trash launched by North Korea, a South Korean lawmaker said on Wednesday,

Over the weekend, North Korea launched a further batch of balloons carrying waste across the border, causing chaos in the south and provoking anger from Seoul officials. The response from South Korea signals that the heightening tensions between the two may soon spill over into a more significant confrontation.

The powerful sister of North Korean leader Kim Jong Un has vowed to boost the country’s nuclear war capability and take other steps to protest the recent arrival of a U.S. nuclear-powered submarine in South Korea.

South Korea warned of possible military actions if North Korea continues to fly more trash balloons across the border, a rare direct threat of retaliation since Pyongyang started sending them in May.

South Korea said Monday it would take "decisive military action" if anyone is killed by the wave of trash-carrying balloons being launched across the border by North Korea.

Mounds of wastepaper and filth will soon be scattered over the border areas and the interior of the ROK [South Korea] and it will directly experience how much effort is required to remove them.’