North Korea threatened Sunday to shell South Korea if it continues to allow activists to launch propaganda leaflets into the Stalinist country.
The North's official Korean Central News Agency said the warning was conveyed to South Korea's military earlier Sunday.
The threats came days after reports appeared saying South Korea's government was mixing propaganda leaflets in with packages containing humanitarian supplies that private activists were floating across the border in helium balloons.
The KCNA also accused Seoul of timing psychological warfare to coincide with annual military drills between the U.S. and South Korea. The drills begin Monday, and last 11 days.
Pyongyang routinely says the annual drills are rehearsals for an invasion of North Korea. Washington and Seoul say they have no intention of invading the North.