North Korea apparently formed a special riot control force late last year to quell public demonstrations. The troops are armed with pistols and batons and trained in crowd control at train stations, town plazas, schools and parks.
A North Korean source said the regime is jittery. "Officials who are deemed an obstacle to the succession" from leader Kim Jong-il to his son Jong-un “are being purged, and fears are mounting among high-level officials that they will be replaced by supporters of Kim Jong-un."
Minister of People's Security Ju Sang-song was sacked in March, apparently because a rival charged him with accepting bribes. And Ryu Kyong, a deputy director of the State Security Department and formerly one of the closest aides to Kim Jong-il, was purged early this year, also following corruption allegations from officials close to Kim Jong-un.
Kim Jong-un has apparently begun a massive audit of the People's Security Ministry and the State Security Department to appoint supporters in key positions there. In the key posts of the Workers Party and the military, the North is apparently in the process of replacing older mid-level officials with people in their 30s and 40s, who will form the support base for Kim Jong-un, while appointing officials in their 40s at key positions within the party.
The source added the reason North Korea took the radical step Wednesday of revealing secret contacts with South Korea and rejecting a summit is because the complicated internal situation makes dialogue impossible at the moment.