Even more worrying is the fact that terrorists and hardcore criminals lodged in Tihar Jail continue to plan kidnappings, murders, and arms smuggling despite being behind bars. The arrest of eight members of the Babloo Srivastava gang last year revealed that Srivastava, who is in Naini Jail, and his right hand man Vinod Tyagi, who is still in Tihar Jail, were communicating with each other as well other members of their gang on mobile telephones.

Last month, the north district police arrested three youths for their involvement in the murder of a former accomplice of notorious criminal Jaswinder Singh alias Jassa. Though Jassa is currently an undertrial in Tihar Jail, he is suspected to have planned the murder of his former associate because he had been cheated of his share from the extortions that the latter had carried out. The police found that Jassa not only met his other associates regularly in the visitor's room at the jail, but also maintained contact with them on the mobile telephone.

Investigations into yesterday's 18 kg RDX haul from a truck at Punjabi Bagh also revealed that three members of the Babbar Khalsa group -- a terrorist outfit from Punjab -- part of the conspiracy to smuggle the explosives into Delhi.Sources said that these three terrorists were also using mobile telephones to communicate with other members of the group.

Another aspect which has been reaffirmed following the seizure is that the police check posts on the Capital's borders do not deter criminals from entering the city or even smuggle in arms and explosives to their hideouts.

``The border is very long, but I don't know if it is porous,'' said V.N. Singh when this was pointed out to him. The Delhi Police is believed to have contacted their Punjab counterparts about the possibility of a fresh threat from terrorists based in that state.

Efforts are also on to prevent undertrials and hardcore terrorists from planning bomb blasts and other activities in the future.