Terming the new trend of secessionist and militant groups in Jammu and Kashmir allying with 'outside elements' to create an impression of turmoil in the State as 'worrisome', Dr Singh hinted at Pakistan's involvement in the terrorist activities in India.
He also said that the infiltration was on a rise and that the encounters with armed militants have become more frequent in recent weeks and months.
However, the Prime Minister went on to say that Naxalism was a bigger threat than cross-border terrorism.
The Prime Minister was addressing the concluding session of two-day conference organised by the Intelligence Bureau on Tuesday, Sep 15.
Union Home Minister, P Chidambaram who spoke at the conference on Monday, Sep 14 too raised concerns over national security. He spoke of the disturbing alliance between Maoists and northeast insurgents apart from questioning the way police are transferred arbitrarily.