Dozens of North Korean balloons filled with trash were spotted in Seoul and the surrounding Gyeonggi Province on Sunday, prompting authorities to scramble to detect and retrieve them.

North Korea once again sent balloons presumed to be carrying trash to South Korea on Saturday, the Joint Chiefs of Staff said, after it launched nearly 1,000 similar balloons across the border since last week.

The latest balloon campaign came after South Korean civic groups' launch of large balloons carrying anti-Pyongyang propaganda to the North between Friday and Saturday.

The Seoul metropolitan government said it has received reports of about 30 of these balloons as of 8 a.m.

Gyeonggi Province and Incheon, a port city west of Seoul, also reported balloons in various locations, including at the Yellow Sea and other residential areas south of the border with North Korea.

So far, no casualties or property damage have been reported.

Authorities advised people not to touch the objects and to report them to nearby military or police authorities, warning of possible damage from the balloons.

The government said it will operate an emergency response team to ensure public safety and consult with military authorities to come up with "fundamental measures" against Pyongyang's repeated balloon campaigns.

"North Korea is once again conducting despicable provocations by sending trash balloons to our civilian regions," Seoul Mayor Oh Se-hoon wrote on Facebook on Saturday night.

In response, the defense ministry issued an emergency order for all troops to be on standby.

"Our military is taking North Korea's additional launches of waste balloons very seriously. It is crucial for the defense ministry and the entire military to remain in a heightened state of vigilance and operational discipline to respond immediately to North Korea's sending of trash balloons and additional provocations," the ministry said. (Yonhap)