Unidentified youths on Tuesday blocked a portion of the Imphal-Dimapur National Highway at Senapati area in Manipur, disrupting traffic movement demanding immediate release of 13 NSCN (I-M) cadres, official reports said.

The 13 persons were on their way to Tamenglong district via the Imphal-Tamenglong road to attend a meeting on 'political awareness', slated for Wednesday, when police arrested them on Monday at Tulibari area of Senapati district, 35 km from Imphal. One AK-56 rifle and an M-20 pistol were recovered from their possession, the sources said.

Those arrested included the NSCN (I-M)'s home secretary A K Lungalang, deputy secretary (publicity) K Chawang and senior member David Pere. They were detained at the Imphal police station.

The NSCN (I-M) claims the action is violates its ceasefire agreement with the Centre. "This is a deliberate attempt to sabotage the Indo-Naga peace process, which has now embarked on a crucial stage," V S Atem, convener of the NSCN (I-M) steering committee, said.

Local youths erected a roadblock on Imphal-Dimapur NH 39 stopping all vehicles in protest against the arrest. All long-distance buses going to neighbouring states were stopped near Senapati, 50km from Imphal, while passenger buses coming to Imphal were stranded at Mao Gate on the Manipur-Nagaland border, reports said.

Official sources said adequate forces could not be deployed in the Senapati and Mao areas because of lack of personnel.