A pro-unification organization in South Korea on Thursday denounced a planned US congressional hearing on the country's ban on the sending of anti-Pyongyang leaflets into North Korea as an "interference in inter-Korean affairs."

The North Korean Committee for the June 15 Joint Declaration said the leafleting ban was legislated on the back of "public consensus" in the South, as a bipartisan caucus of the US House of Representatives is set to hold the hearing on Thursday (US Eastern time).

"The hearing is an interference and interruption in inter-Korean affairs," the group said during a press conference in front of the US Embassy in central Seoul.

With regard to a State Department official's reported remarks that South Korea has a tool to review the law, the organization accused Washington of violating South Korea's national sovereignty.

It stressed that the law's main objective is to protect the safety of people living in border regions where such leaflets usually had been sent via balloon, rendering the areas vulnerable to attacks from the North.

In December, the National Assembly, controlled by the ruling Democratic Party, approved a bill penalizing the sending of anti-Pyongyang propaganda leaflets into North Korea despite strong objection from opposition party members, claiming it is aimed at protecting the safety of people living in border towns

The ban came months after the North blew up a joint liaison office in protest, and critics have claimed the legislation is tantamount to caving to Pyongyang's pressure.

Critics have also said the legislation could erode freedom of expression and block one crucial avenue for sending free world information into the reclusive country. (Yonhap)