Four North Korean defector groups launched balloons loaded with snacks and other items towards North Korea on Friday.

The North Korea Peoples' Liberation Front says it joined three other organizations in dispatching the balloons from near the port city of Incheon.

Defectors say they loaded 20 large balloons with snack cakes, compact discs and informational leaflets.

North Korea has lashed out at previous balloon launches, threatening to shell South Korea in response to such actions, which it calls deliberate provocations by Seoul that could lead to war.

Meanwhile, a separate aid shipment from South Korea is expected to reach the north sometime next week.

South Korea's Unification Ministry said Friday it is allowing a group of civilians to deliver 180 tons of flour to North Korea, the first such shipment since the death of former leader Kim Jong Il.

South Koreans are not permitted to travel to North Korea without government permission. Seoul cut off government aid to North Korea after President Lee Myung-bak took office in 2008.