(QHA) -

Activists in South Korea, including some North Korean defectors who were soldiers when they lived in the North, sent propaganda-loaded balloons over the border into North Korea on Wednesday, defying Pyongyang's past threats of retaliation against the launches, Voice of America reports.

The helium-filled balloons were stuffed with DVDs and leaflets documenting human rights abuses in the North. They also contained 1,000 U.S. one-dollar bills and small USB drives loaded with the Korean-language version of Wikipedia.

Thor Halvorssen of the U.S.-based Human Rights Foundation, which helped organize the launch, called the balloons "controversial," but said it is crucial North Koreans be allowed to access information the rest of the world already enjoys.

South Korea is watching the North closely following last month's execution of Jang Song Thaek, the powerful uncle and mentor of North Korean leader Kim Jong Un. Jang was accused of plotting a coup, raising fears of instability in Pyongyang.

Some analysts have said North Korean leaders could carry out another nuclear or long-range missile test in order to build internal unity.