Dismissing India's contention that Pakistan's Inter Services Intelligence agency could be involved in the recent blasts in various cities, Pakistan on Thursday said that such allegations could vitiate the atmosphere for the ongoing Composite Dialogue process.

"Pakistan rejects the allegations leveled by the National Security Adviser of India, M K Narayanan, about the suspected involvement of ISI in Ludhiana, Ajmer and Mecca Masjid blasts and the so-called attempts by Pakistan to build up a radical Sikh environment," Foreign Office spokesperson Mohammad Sadiq said in Islamabad on Thursday.

Narayanan was quoted by an Indian newspaper as saying, "there is no connection between the blasts in Ludhiana, Ajmer and Mecca Masjid, other than the fact that the ISI's involvement is suspected in all of them."

On the Ludhiana blast that left six people dead, he said, "there has been a manifest attempt in Pakistan to build up a radical Sikh environment."

Sadiq said: "Indian officials are in the unfortunate habit of making such unfounded allegations whenever a violent incident occurs in India. The timing of these allegations is especially regrettable because they could vitiate the atmosphere during the bilateral talks on confidence-building measures taking place in New Delhi."

Indian and Pakistani officials held two-day talks in New Delhi on various confidence-building measures, including nuclear and conventional CBMs.