Security forces have busted 33 kidnapping rings over the past year in Afghanistan, Spokesman for National Security Directorate (NSD) Syed Ansari said Thursday.

The busted criminal gangs included 33 groups of 114 people. Six groups were from capital Kabul, which were involved in abduction of traders and businessmen for ransom, Ansari told journalists at a news conference.

He also said that the kidnappers released their hostages after receiving ransom from their families.

Thirty-five people have been released from the kidnappers' custody during operations, the official said.

Some of the ring leaders, he stressed, are living outside the country and the efforts to bring them to justice are continuing.

Kidnapping for ransom and security incidents in the post-Taliban Afghanistan have forced a considerable number of investors to leave the country for neighboring states and Dubai.