North Korea launched more balloons likely carrying rubbish toward South Korea on Sunday, two days after the South restarted blaring anti-Pyongyang propaganda broadcasts across the border in retaliation for the North's repeated balloon campaigns, Seoul officials said.

South Korea's Joint Chiefs of Staff said the North Korean balloons were flying north of Seoul, the South Korean capital, after crossing the border. It said the South Korean public should be alert for falling objects and report to police and military authorities if they see any balloons fallen on the ground.

North Korea's latest balloon flying is threatening to escalate tensions on the Korean Peninsula. South Korea earlier warned it would conduct loudspeaker broadcasts in a fuller manner and take other stronger steps if North Korea continues provocations like balloon launches.

Since late May, North Korea has floated numerous balloons on a series of launch events to drop scraps of cloth, cigarette butts, waste batteries and even manure, though they caused no major damage in South Korea.

North Korea said the initial balloons were launched in response to South Korean activists sending political leaflets to the North via their own balloons.

South Korea responded by suspending a 2018 tension-reduction deal with North Korea, making propaganda broadcasts and conducting front-line live-fire military drills at border areas.