A large balloon presumed to have been sent by a conservative South Korean civic group to fly anti-North Korea leaflets crashed into the southern waters off Busan on Saturday.

Attached at the bottom was a timer designed to cause the balloon to explode after a certain amount of time elapsed, but there were no leaflets inside the balloon.

Immediately after retrieving the balloon, police, the military and the National Intelligence Service, the state intelligence agency, launched a joint probe to know whether the balloon, typically used to carry propaganda leaflets from either of the two Koreas, is from the North.

They, however, concluded that it has nothing to do with the North because it is identical to the balloons used by a conservative South Korean group to send anti-Pyongyang leaflets across the border into the North.

The transparent balloon, 3-meters-long and 1-meter-wide, was first spotted by a rescue swimmer on duty at the Haeundae beach in Busan, at about 9:20 a.m., according to the Busan regional firefighting headquarters. It crashed into the sea about 25 minutes later before drifting rightward toward Dongbak Island. The timer has remained undetonated.

The Busan Coast Guard later dispatched a patrol boat to retrieve the balloon at the request of the firefighting authorities.

In May, a large balloon carrying materials suspected to be anti-Seoul propaganda leaflets from North Korea was found hanging across electrical wires near an elementary school in Eunpyeong district, northwestern Seoul. (Yonhap)