Islamabad has refused permission to a team of India's National Investigation Agency (NIA) to visit that country to interrogate the masterminds of the 26/11 Mumbai terror attacks and gather evidence against them.The refusal comes at a time when New Delhi is considering a request from Pakistan to send a judicial commission to this country to interview key witnesses and other officials in connection with the trial of seven suspects in 26/11 Mumbai terror attacks case in Pakistan. Official sources said that in a communique, Islamabad conveyed to New Delhi that the law of that country does not allow a probe by any foreign agency in any case there.Islamabad also told New Delhi that there was no Mutual Legal Assistance Treaty between the two countries and so the request cannot be accepted.Pakistan's refusal to allow the NIA team to visit that country was another tactic to delay the probe into Mumbai terror attack case as New Delhi would like to send the team only after approval of the relevant court.