South Korea on Sunday vowed to take "unendurable" measures against the Democratic People's Republic of Korea (DPRK) for sending trash-filled balloons across the border, Yonhap news agency reported citing National Security Adviser Chang Ho-jin.

Chang made the remark at a meeting of the National Security Council, the first such gathering over Pyongyang's balloon operations.

The DPRK sent hundreds of balloons carrying trash and excrement across the heavily fortified border on Tuesday and Wednesday, dubbing them "gifts of sincerity." Seoul has responded angrily, calling the move base and dangerous.

On Sunday, South Korea's Joint Chiefs of Staff again accused the DPRK of sending some 600 trash-carrying balloons over since Saturday. 

The DPRK's "flying of trash balloons and GPS jamming are such despicable provocations that could not have been imagined by a normal country," Chang was quoted as saying by Yonhap.

South Korea is not ruling out resuming its loudspeaker propaganda campaign, a high-ranking official in the presidential office was quoted by Yonhap on the condition of anonymity.

South Korea stopped blaring propaganda across the border in 2018 after a rare summit with the DPRK leader Kim Jong Un.

(With input from agencies)