North Korea flew hundreds of trash-carrying balloons toward South Korea in one of its most bizarre provocations against its rival in years, prompting the South's military to mobilise chemical and explosive response teams to recover objects and debris in different parts of the country.The ballooning campaign came as North Korean leader Kim Jong Un urged his military scientists to overcome a failed satellite launch and continue developing space-based reconnaissance capabilities, which he described as crucial for countering U.S. and South Korean military activities, state media said on May 30.