India Tuesday demanded Pakistan conduct a "credible crackdown" on militant groups after one of the alleged masterminds of the 2008 Mumbai attacks 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 terrorist attack and terrorist organizations involved in cross-border terrorism would be proof of Pakistan's sincerity," it added in a statement. Meanwhile, supporters of Saeed held in Pakistan's major cities on Tuesday after authorities detained Saeed after years of pressure to act against his group. Firebrand religious scholar Hafiz Saeed, who heads the Jamaat-ud-Dawa (JuD) group and has a $10 million US bounty on his head, is to be placed under "preventative detention", according to an order from the interior ministry. Police took Saeed away from a mosque in Lahore late Monday and escorted him to his residence where they appear to be holding him under house arrest, a journalist reported. "My detention orders are unlawful and we will challenge them in the court," Saeed told reporters before he was led away by police. "These orders have come from Washington," he claimed. JuD, listed as a terror outfit by the United Nations, is considered by the US and India to be a front for Lashkar-e-Taiba (LeT), the militant group blamed for the attack on India's financial capital. Saeed is believed by the US State Department to be one of the masterminds of the attack. JuD organizers said on Tuesday that protests were planned in major cities including Islamabad, Karachi and Lahore. A spokesman for the group, Nadeem Awan, confirmed the detention order would be challenged in court. The horror of the Mumbai carnage played out on live television around the world as commandos battled the heavily armed gunmen, who arrived by sea on the evening of Nov. 26, 2008. It took the authorities three days to regain full control of the city and New Delhi has long said there is evidence that "official agencies" in Pakistan were involved in plotting the attack. Islamabad denies the charge.