North Korea sent another barrage of trash-bearing balloons over the border on Monday, with South Korean authorities revealing that they have found small amounts of explosive material connected to balloons’ timer mechanisms.

South Korea’s Joint Chiefs of Staff (JCS) issued a statement about the launch at 5:48 a.m., warning that “there is a possibility that the presumed North Korean trash balloons will travel to the Gyeonggi Province and the metropolitan area when considering wind direction.”

Seoul city authorities also issued an alert at 5:46 a.m. warning residents to be cautious of falling debris and report any findings to the military