NEW DELHI - India Tuesday demanded Pakistan conduct a "credible crackdown" on militant groups after Hafiz Saeed was detained at a mosque in Lahore. "Exercises such as yesterday's orders against Hafiz Saeed and others have been carried out by Pakistan in the past also," India's foreign ministry said after the leader of the Jamaat-ud-Dawa (JuD) group was placed under "preventative detention" on Monday night. "Only a credible crackdown on the mastermind of the Mumbai attack and organisations involved in cross-border terrorism would be proof of Pakistan's sincerity," it added in a statement.