Opposition leader Lee Jae-myung on Saturday said the two Koreas should sit together and communicate to ease the escalating tensions over Pyongyang's trash-carrying balloon campaign and Seoul's response.

On social media, Lee said the peace built up on the Korean Peninsula is at risk as the two Koreas have been engaged in tit-for-tat measures.

Referring to the North's sending of balloons carrying trash across the border, South Korean civic group's sending of anti-Pyongyang leaflets and the suspension of the inter-Korean military pact, Lee said North Korea should stop provocative actions and seek to establish an eternal peace regime, which was reflected in the June 15 Declaration, the joint declaration for the two Koreas' first inter-Korean summit on June 15, 2000.

"(The South Korean government) should realize that ordinary citizens and residents near the border will bear any damage should it stick to a hard-line, eye-for-eye stance," Lee said.

Tensions have recently heightened on the Korean Peninsula after Pyongyang sent over 1,000 balloons carrying trash to the South since late May in what it claims is a response to anti-Pyongyang leafleting.

The move eventually led South Korea to fully suspend a 2018 inter-Korean tension reduction pact and resume propaganda loudspeaker broadcasts near the border for the first time in six years.

Defector groups in the South have sent balloons carrying leaflets and other goods across the border, although such acts are banned in the country under a law that was legislated during the previous administration to help reduce tensions in the border regions.