The influential sister of North Korean leader Kim Jong Un has warned of a new response if South Korea continues to broadcast loudspeakers and distribute leaflets amid rising tensions.

“If the ROK simultaneously launches provocations by distributing leaflets and making loudspeaker broadcasts along the border, it will undoubtedly witness new retaliatory actions from the DPRK,” Kim Yo Jong said late Sunday in a statement carried by state news agency KCNA, using the official names of South and North Korea.

South Korea resumed loudspeaker broadcasts to North Korea on Sunday, its military said, after a warning that Pyongyang should stop sending balloons carrying garbage to South Korea.

“This is the prelude to a very dangerous situation,” Kim, a deputy department director of the ruling Workers’ Party, said, referring to the South’s loudspeaker broadcasts.

South Korea’s military said the decision to resume broadcasts, intended as a form of psychological warfare, was taken after North Korea released about 330 balloons containing garbage on Saturday, about 80 of which fell across the border.

Pyongyang began sending balloons filled with garbage and dung across the border in May, saying the move was in retaliation for South Korean activists flying anti-North Korea leaflets as part of a disinformation campaign.

North Korea has reacted angrily to leaflet campaigns and loudspeaker broadcasts, and in some cases has even fired weapons at balloons and loudspeakers.

South Korea halted the transmissions in 2018 under an agreement signed by the two Korean leaders, but tensions have since risen as Pyongyang has stepped up weapons development.

South Korea’s broadcasts mix popular K-pop music with world news and information about democratic and capitalist society. The sound is believed to travel more than 20 kilometers (12.4 miles) into North Korea.