New Delhi, Mar 12 (ANI) Union Home Minister P Chidambaram on Friday said that Pakistan is a difficult neighbour.

Interacting with the audience at the "India Today Conclave 2010," Chidambaram said: "Pakistan is a difficult neighbour" and added that Kashmir is the key problem between the two.

"It is no secret that the ISI gets its support from Pakistan-based terror groups that run modules in India," Chidambaram said.

Chidambaram stressed the need for India and Pakistan have a dialogue to find an amicable solution to their problems.

"The two nations are nuclear powers and war is not an option. So, we must talk. At other times, we must remain vigilant," he added.

Commenting on what would be India''s response if a Mumbai-style attack happened again, Chidambaram said: "If it is reasonably established that any 26/11 attack in future has its origin in Pakistan, India''s response will be swift and decisive."

When specifically pressed about whether India would opt military action as a response to such acts, Chidambaram said: "You can ask the question once the prompt and decisive action takes place."

Chidambaram also asked Pakistan to verify the voices on the transcripts of the handlers of the 26/11 attacks.

 He expressed his displeasure over Pakistan''s non-cooperation in the 26/11 probe.